Maximise your Avios, air miles and hotel points

Should UK airport slot rules be changed? We look at the issues and options

Links on Head for Points may support the site by paying a commission.  See here for all partner links.

The UK Government has just launched its first consultation on airport slots in over thirty years.

With a third runway at Heathrow stalling (again) and expansion plans at other airports being downsized, adjustments to slot allocation rules may be the only way to increase overall capacity at airports.

“Given the current capacity constraints … and the likelihood of these worsening without new capacity, the Government believes that it is essential that the utilisation of existing capacity is fully maximised.”

Should UK airport slot rules be changed?

You can read the consultation document here. Despite being 92 pages long (!) it is a surprisingly informative introduction into the slot allocation process.

The consultation will only apply to so-called ‘Level 3’ slot coordinated airports, ie. the most congested airports in the country. These are:

  • London Heathrow 
  • London Gatwick 
  • London City 
  • London Stansted 
  • London Luton 
  • Manchester 
  • Birmingham 
  • Bristol 

The consultation will gather feedback on a variety of ideas to increase the efficiency of existing airport operations to make the best use of the infrastructure in place. The objectives for the slot reform are:

  • “Stimulating a competitive environment by creating a more efficient, transparent, and dynamic slot market”
  • “Establishing a framework for the allocation of new slots”

What are airport slots, anyway?

Fundamentally, an airport slot is a landing or take-off right for a specific date and time at an airport. Use of runways and taxiways is carefully divided into small increments that are allocated to airlines so that they can build their own flight schedules. It ensures that airports run smoothly and efficiently.

At the busiest airports, such as Heathrow, slots are lucrative in themselves and can fetch millions of pounds. In 2017 Oman Air paid a record $75m for a sought-after early morning slot at Heathrow.

To operate a flight, an airline needs two slots – one for landing and one for take-off – so there are twice as many slots as flights.

Slots only become an issue when more airlines want to operate into an airport than the airport can accommodate. This can come down to a number of factors, including the number of runways, terminal capacity or regulatory restrictions such as a flight cap.

At Heathrow, for example, the biggest constraint is the number of runways which can only facilitate so many flights per day.

Should UK airport slot rules be changed?

How are slots currently allocated?

Under the current system, there are two criteria for awarding slots.

By far the largest proportion of slots, at Heathrow at least, are awarded under so-called ‘Historic Rights’. This means that if you have a slot in the previous summer or winter flying season you get to keep it for the next one. This is one of the reasons why British Airways owns 51.8% of all Heathrow slots – it inherited many of them from its predecessors such as BEA, BOAC and bmi.

To keep a slot, the airline must abide by the 80:20 ‘use it or lose it’ rule in which the slot is used at least 80% of the time. As long as it does so, it can keep the slot in perpetuity.

Any slots that are not allocated under historic rights are allocated under a set of guidelines that take into account connectivity, competition and various other operational factors.

Slot coordination was introduced in 1993. Prior to that, the flag carrier of a country was responsible for allocating slots. It doesn’t take a rocket scientist to see how that might be anti-competitive!

Pre-empting the introduction of regulatory slot coordination, British Airways split out its slot coordination department in 1991 to create Airport Coordination Limited. This is now the world’s largest airport slot coordinator, working with 72 airports.

When rules around historic and secondary slot rights were introduced, airline demand for slots was below available capacity. This meant that airlines were largely free to launch and operate flights at UK airports ad-hoc without having to worry about securing slots.

That has since changed, of course. Through various mergers and buy-outs, British Airways now owns the 51.8% of all Heathrow slots with second-best Virgin Atlantic coming in with just 4.3%. The situation is similar with Gatwick and easyJet. This obviously bestows huge competitive advantage on the incumbents.

This is a problem, because it means the airport marketplace becomes (in the words of the government) “undynamic”:

“However, the combination of airport capacity being congested and the majority of slots at an airport being held by one or two airlines can inhibit competition and lead to the slot allocation system becoming undynamic …. If an airline loses a slot at a capacity constrained airport it can be very difficult, or take many years, for the airline to acquire a new one. It is often only when an airline becomes insolvent that significant numbers of slots become available at a capacity constrained airport. The impact of this is that there are fewer opportunities for new airlines to commence services at an airport or for existing airlines at the airport to grow, limiting choice and connectivity for businesses and passengers.”

To put this into perspective, 99% and 98% of slots are allocated based on historic rights at Heathrow and Gatwick respectively. Even though at least 50% of the remaining slots must be allocated to new entrants, it’s very hard for airlines to launch new flights at these airports.

JetBlue is a prime example of this, having struggled to get a foothold in the London market. It has had to split its operations across Heathrow and Gatwick, increasing its cost base and lowering its efficiency.

Should UK airport slot rules be changed?

How could the slot allocation process change?

Now that we are no longer part of the EU, the UK Government has greater latitude to reform the slot allocation process. However, an airline obviously needs slots at two airports to operate an international flight so there has to be an element of standardisation.

The consultation document pitches a number of different options that it could consider:

Increasing slot utilisation and the ‘use it or lose it’ rule

One of the options on the table is to increase the number of flights an airline must operate in order to retain its slots. At present, that is 80%. For example, if an airline had slots for a flight every single day of the year, it would only have to operate flights on 292 days in order to meet this rule.

The consultation document suggests that this could be increased to a higher level, such as 90%. Whilst this would be great for efficiency and mean the runways and airport facilities are being used at a higher capacity, there are a few reasons why it could backfire:

  • Unused slots provide some resilience and redundancy during times of disruption. The higher the utilisation rate the closer you are to operating the airport at 100% capacity. When things go wrong and flights are delayed or cancelled, you have less of a buffer to reschedule flights and recover.
  • Increasing the utilisation rate could increase the number of ‘ghost flights’ during quieter periods of the year. These are flights that are operated for the sake of retaining slots – sometimes without even carrying passengers. There are obviously environmental issues with this approach too.

Slot routing restrictions and retiming

At the moment there are a number of slot rules that give incumbent airlines preferential treatment over new entrants.

This includes the fact that new slots allocated to incumbents can be used for any route whilst new entrants must use their slots for the allocated route for at least two flying seasons (one year) before they can use them for other destinations.

In addition, incumbent airlines are able to re-time their slots during the coordination process before any remaining slots are re-allocated. This means that existing airlines have a competitive advantage over new airlines, particularly when an airline goes bust or ceases operations at an airport and leaves a void. Existing airlines are able to cherry pick the more preferable slots, leaving little on the table to interest new entrants.

In both cases, the Government is proposing to level the playing field between incumbent airlines and new airlines. It proposes that all new slots should be treated the same, with a moratorium of four flying seasons (two years) until airlines can fly to alternate destinations. It also suggests that the re-timing advantage be removed and that re-timing requests and new slot requests be considered at the same time.

Both of these suggestions seem eminently sensible to me.

The Government wants greater control of the slot coordinator

At the moment, slot coordination is managed by a range of private companies which are contracted by airports to manage their slot portfolio. The largest of these is ACL, which I mentioned above.

This means that the Government has no control over slot coordination beyond regulatory and policy framework. It wants to change this.

The consultation document proposes to create a new power for the Secretary of State:

“to issue a direction to the coordinator requiring it to undertake a certain action. Any direction would need to be in keeping with Regulation (for example a direction could not require the coordinator to do something which is not within its remit). We do not believe that it would be appropriate for the Government to have the ability to direct the coordinator on the allocation of individual slots or to take action which would unfairly benefit a particular airport, airline or country.”

The great slot trading marketplace

When slot coordination was first introduced in the 90s, nobody expected slots to become tradable commodities or sell for tens of millions of pounds.

In 1999 the UK High Court confirmed that whilst slots are not the property of the airline, they are allowed to be traded or sold between airlines however they wish.

In a 2019 report, Frontier Economics said that a daily, year-round Heathrow slot pair was worth around £15m for early morning slots, £10m for mid-day slots and £5m for evening slots. Clearly, trading and selling slots is big business.

Unfortunately, because slot coordination was not designed with trading in mind there is no official marketplace or register and there is a “lack of transparency over who holds and operates each slot”.

To solve this problem, the Government is proposing to establish a compulsory public slot register for airports as well as a mandatory trading platform:

“It is envisaged that ACL would be responsible for providing and maintaining the platform. At the very least, slots that are available for trading would be required to be advertised on the platform.”

It also wants to give the slot coordinator regulatory oversight to review and approve all slot trades.

These are good changes, I think, although arguably slot trading should be scrapped altogether.

A fairer system would be to require airlines to forfeit their slots to the allocation pool should they no longer have any need for them. This would allow the slot coordinator to re-allocate slots based on the most attractive bidder, rather than the airline with the most money. It would allow the slot coordinator to be more strategic and prioritise additional competitors or new routes.

Should UK airport slot rules be changed?

Slot leasing …. in perpetuity

Slot leasing is a related issue.

At present, airlines are able to lease out their slots for an indefinite period of time, allowing them to retain their slot portfolio until such a date as they should require them. This means that some slots are retained by airlines for no other reason than they can make money by leasing them to other airlines.

The consultation document quite sensibly writes that:

“It is the Government’s view that an airline should not use leasing to hold on to a slot for an extended period which it has no use for. Leasing should not be used as a long-term operational solution and slots should instead be returned to the pool for reallocation.

We are proposing that slot leasing is limited to a set period after which the slot will have to either be returned to the pool or flown by the original slot holder.”

Conclusion

A lot of these suggestions seem quite sensible, which probably means the airlines won’t like them.

The Government is also proposing to reform the way new slots are allocated, which I haven’t touched on. This could have a significant impact given the proposals for a third runway at Heathrow and Gatwick’s plans to bring its Northern taxiway into use as a runway.

Incumbent airlines such as British Airways would love to see any new capacity pro-rata’d based on existing slot ownership whilst others would take the opposite view and would prefer it to go to challenger airlines.

It will be interesting to see what the results of the consultation are, which runs until 9th February.

Comments (93)

This article is closed to new comments. Feel free to ask your question in the HfP forums.

  • BJ says:

    I think the government is barking up the wrong tree here. I think they would be much better ‘interfering’ in the market place to promote expansion of regional airports to simultaneously develop the regions and reduce pressure on the SE airports. I am not sure what percentage of traffic is due to regional connecting passengers but I’m sure at LHR it is sufficiently significant to make a difference. As far as slots at LHR and other capacity-consrained airports are concerned I think they need to factor in aircraft type and route frequencies. I get that business travellers value frequencies but what proportion of total passengers are business travellers, I’m guessing that even at LHR most are leisure? Where slots are a problem it seens bonkers to me to be flying a route 7 or 8 times a day with a 787-8 when they could fly it 4 or 5 times daily with an A380 or 777-300. Incentives could be used to use larger aircraft and reduce frequencies.

    More like this from Rhys please and less flight and hotel reviews.

    • Rhys says:

      Most of the A380s are already being used on routes where multiple daily frequencies are needed because the A380 does not offer enough capacity, eg Joburg, LA, Miami etc. No larger aircraft exists!

      • Richie says:

        But, apparently, the A380’s wings are big enough for a stretched fuselage.

        • Rhys says:

          ….did you miss the memo on Airbus ending A380 production a few years ago? 😉

          • Richie says:

            It would’ve been good to have had an A380-900, but it ain’t going to happen.

          • BJ says:

            And Emirates CEO apparently said in an interview recently that they may remain interested in buying more. With future passenger growth and even more crowded airports I would not betvagainst an A380neo at some point. I hope so, it is so much nicer than the rest IMO.

      • BJ says:

        The consultation is about the future; regulations, policies and markets can all change. Besides the A380 is not the only large aircraft.

    • jjoohhnn says:

      BA said 75% of their custom is leisure travel so you can extrapolate that to LHR I imagine.

  • Simon says:

    Fascinating article. I’d love to know if there are knock on ramifications at the destination end? Sure a challenger airline can get a slot at 13:15 on a Monday but how does that factor in to a slot they can get at a destination airport suitable for a plane type they have available for that slot.

    • Rob says:

      Exactly. It’s a 2-way process. Which is what people forget when they say, for eg, BA should fly an A380 to xxxxx when xxxxx may not be A380 certified or have enough A380 gates.

      • jjoohhnn says:

        But the ‘home’ end country is going to be less of an issue a lot of the time. If you consider JetBlue, if they got more slots at LHR then they would have no qualms about dropping or re-timing a domestic at JFK so they could use the slot at JFK on the LHR route. The same would apply for other airlines generally where they already have a home market.

        New entrants would have more of a problem, like Norse Atlantic perhaps where they would need to get coordinated slots between JFK and LHR, or Global Airlines. This is where slot leasing is actually useful to new entrants because it gives airlines more options over the slots they have access to.

        These new rules on limiting leasing could perhaps hamper an airlines ability to launch. Would Global Airlines launch from LHR if their only option is leased slots and the Government introduce a 1-year limit?

      • BJ says:

        They only have 12 I think so they cannot send thrm much of anywhere. With longer range and more efficient narrow body aircraft becoming available regional point to point might become more common partly alleviating pressure.

    • Dubious says:

      Whilst there is a dependency on airport capabilities, the slots generally don’t specify the aircraft type. The type of aircraft being used is generally influenced by the airport fee regime.

      A more noticeable issue is the adherence to noise restrictions. The timing of flights between Europe and the Middle East are generally constrained by the operating hours of airports in Europe.

      The whole slot negotiation process is surprisingly manual.

  • Panda Mick says:

    This is a great article! Whilst none of us are fortune tellers, nothing good will come of this for BA…

  • BBbetter says:

    All nice to read, until IAG makes a payment to the Tory party.

  • dougzz99 says:

    The Government definitely need to take direct control of the slot allocation process. How else can individual ministers benefit personally from their balanced and unbiased decisions.

  • Nick says:

    I suspect this consultation will get caught up in the end of the current parliament and election for a new one, then will quietly be dropped. Which is a shame, because the measures are indeed on the whole very sensible.

    The biggest insight to come out of it though was that little old Bristol is also slot constrained!

  • Matarredonda says:

    Very interesting article.
    Woa beside us if we allow Government to get more control as they are totally corrupt and will make decisions for political expediency whereas now, at least in theory have an opportunity.
    US Airlines will always try bully boy tactics if they don’t get what they want and ME Airlines just get as much money from the state as needed to buy the slots it wants.
    Cynical? Yes defo. as soon as Government starts meddling with the rail industry a prime example.

  • Michael Jennings says:

    Honestly, to promote competition the best thing would be to remove historic rights entirely. The whole system exists to protect incumbents from competition. This is unsurprising given that incumbent airlines set the system up. The entirety of an airport’s slots for a season should be auctioned a year or so ahead, and therefore new entrants would have access and the slots would be used by whoever finds them the most economically valuable.

    Given that large portions of the economic value of incumbent airlines are tied up in their ownership of slots, though, this isn’t going to happen. The various tweaks suggested in the report are all generally good ideas, but they are messing around with small details rather than fundamentally changing everything. The exception is the process for allocating new slots in the event that a large number of new slots become available at Heathrow or Gatwick at once, which would happen in the event of opening a new runway. Getting this right – again I think ideally through an auction – is very important.

    • Rhys says:

      You can’t remove historic rights entirely, as airlines would have no ability to plan more than a year in advance. That’s a problem when you need to maintain a fleet of very expensive aircraft but don’t know how many you can actually fly next year!

      Imagine if BA got 100 slots one year but 1000 the next. It wouldn’t work.

      • Michael Jennings says:

        As long as there are clear rules as to how and when the auctions for slots for future years will take place and that the slots will be available to be auctioned, this shouldn’t be a problem. (You would also need a proper secondary market for airlines than change their plans). Airlines don’t necessarily know what the price of them will be, but that is true of a lot of their other costs too – they don’t know what the cost of fuel will be either. If it turns out that some of the slots are so expensive that the services are no longer economic, then they can redeploy some of their aircraft elsewhere. just as they do now in response to a lot of factors. Some other airline that can use the slots more efficiently will use them instead, which is the entire point of the exercise.

        If airlines want to be certain of their costs more than one year ahead, financial markets are very good at creating hedging schemes for uncertain future costs. You could also sell the slots more than one year ahead (and in fact create something similar to the bond market with lots of different slot types with different maturities and expiry dates), but it would probably be better to keep the basic allocations simple and let the financiers create the derivatives.

        The key point is that the problem is that at present slots are issued in perpetuity, and this creates a huge advantage for incumbents and disadvantages new entrants. It would be good for this to change. I don’t think it will, as it would upset incumbents and their shareholders too much. But it would be a good idea. It might be possible to change the rules and give a finite lifetime to new slots without changing the rules for old ones, however, which would be an improvement.

This article is closed to new comments. Feel free to ask your question in the HfP forums.

The UK's biggest frequent flyer website uses cookies, which you can block via your browser settings. Continuing implies your consent to this policy. Our privacy policy is here.