Alaska Airlines launched its first flight from Seattle-Tacoma International Airport to London Heathrow Airport on May 21, marking its debut in the UK and in Northern Europe. The daily service covers 4,171 nautical miles each way and gives the carrier its second European route after Seattle-Rome, which began on April 28.
The new route is being flown on a Boeing 787-9 and uses slots leased from American Airlines, which served the Seattle-Heathrow market itself from 2021 to 2023. Alaska’s own bid for Heathrow slots from the usual pool was rejected outright, leaving it dependent on leased access to one of the world’s most tightly controlled airports.
That matters because the Seattle-London market is already deep and busy. In the 12 months to February 2026, 285,000 round-trip passengers flew between the two cities as local travelers, while the US Department of Transportation counted 533,210 passengers in the examined period. Around 82% of those travelers did not connect onward, and about 51,000 passengers transited en route to or from Heathrow, mainly through Keflavik on Icelandair.
Alaska’s entry comes at a moment when demand is strongest and seats are most expensive. The route was announced last year and opened for booking in December, and it is being launched in the peak summer period. The airline is a oneworld member, and Heathrow’s slot limits mean new long-haul flights generally appear only when an operator can buy or lease access from another carrier.
The daily Seattle-Heathrow flight also changes the schedule on a route that was already crowded. Up to four daily services were available before Alaska arrived, and that number will rise to five. Alaska’s addition is part of a broader European push that now includes Rome and will grow again on May 28, when its third European link, to Iceland, is due to begin.
The question now is not whether Alaska can sell the seats. It is whether the airline can hold its place in a market dominated by scarce Heathrow access and heavy competition long after the summer launch rush fades.
