The latest slot coordination report for (LHR) has shown that two United States airlines, Delta Air Lines and JetBlue, have failed to obtain additional slots at the airport for the upcoming summer season.
Adding flights to London-Heathrow
In the initial coordination report, Airport Coordination Limited (ACL), the company that coordinates slots for over 75 airports globally, published on November 13, showed that out of the four US-based airlines operating flights from/to London Heathrow Airport (LHR), two, and , have failed to obtain additional slots for the upcoming summer season. American Airlines and United Airlines did not request additional slots.
According to the report, Delta Air Lines requested 960 additional slots, while JetBlue asked for 840 slots, which would have enabled both airlines to add extra itineraries on flights from/to the airport serving the British capital.
The International Air Transport Association (IATA) summer season in 2025 will begin on March 30, 2025, and end on October 25, 2025, with the association holding a slot conference between November 19 and November 22.
There, airlines can obtain the slots that would give them the best possible schedule to offer their customers at coordinated airports, the association pointed out.
It'll be the first time Delta has used the aircraft type to the UK.
Growing capacity
The ACL’s report indicated that there was a total demand for 319,223 slots during the season, with the coordinator allocating 290,495 slots to airlines, or 91% of the total demand.
41,284 slots were not cleared due to runway restrictions, while the remaining rights to land and take off from Heathrow were not given to airlines because of arrival and departure turnaround feasibility, terminal constraints, and other reasons.
Nevertheless, three US-based airlines will add more seats on their flights to the airport: , Delta Air Lines, and United Airlines.
American Airlines should add up to 62,200 new seats compared to the previous season, while Delta Air Lines and 
United Airlines plan to increase its capacity on flights to London-Heathrow by 103,830 and 83,580 seats, respectively.
JetBlue will be one of the few carriers that should reduce its total seat capacity to the British capital, with 7,560 fewer seats during the season than in 2024.
Meanwhile, , which is the largest airline in terms of seats at the airport, has 27,930 fewer seats during the upcoming summer season.
Presumably, that was because the airline has had to adjust its long-haul network due to Trent 1000 supply issues from , forcing the British carrier to cut some flights with the Boeing 787.
Overall, aircraft movements at London Heathrow Airport (LHR) will remain flat year-on-year (YoY) but airlines will add 1.3% seats at the airport during the upcoming summer season.
Delhi joins a long list of British Airways destinations that have been affected by supply-side issues with the Trent 1000 engine.
Summer network to the US
According to data from the aviation analytics company Cirium, six airlines will fly from Heathrow to the US in June 2025, which includes the aforementioned four US airlines, British Airways, and .
In total, the half-a dozen carriers will serve 31 destinations in the US with 856 weekly flights, with the most popular destinations being (JFK), Newark Liberty International Airport (EWR), and (LAX).
Which US airports do you think have grown the most to/from Heathrow?
