Alaska vs. Delta in Seattle is the airline rivalry the Pacific Northwest can't stop talking about. Alaska is Seattle's hometown airline and carries about half of the area's airline seats, roughly twice as many as Delta. But Delta has spent more than a decade building Seattle into its own hub, and the two now go head to head on flights everywhere from Phoenix to Tokyo. So I checked which one actually runs on time. I tracked every flight Alaska and Delta flew out of Seattle-Tacoma International Airport on their own planes for a full week, Nov. 4 to 10, about 2,100 departures in all.
The home team lost.
The Results
Delta's flights from Seattle reached their destination gate on time 85.7% of the time, using the government's standard of arriving within 15 minutes of schedule. Alaska came in at 80.8%. That's about one in seven Delta flights arriving late, compared with about one in five on Alaska.
Leaving Seattle, the gap was wider. Delta pushed back from the gate on time on 88.2% of its flights, and Alaska on 79.4%. Delta won six of the seven days. Alaska's only win came on Wednesday, Nov. 4, and it was by a fraction of a point.
Looking only at the 17 cities both airlines fly to from Seattle, Delta arrived on time 86% of the time and Alaska 80%. Delta's biggest leads came on sunny leisure routes, including Phoenix (97% to 86%), San Diego (81% to 67%) and Las Vegas (94% to 88%). Alaska won a couple of its own, with San Francisco (72% to 68%) and Dallas-Fort Worth (88% to 79%). On the coast-to-coast flight to New York's JFK and the flight to Anchorage, the two were basically tied.
Where Alaska Slipped
Alaska's problem wasn't meltdowns. Both airlines had about one in 22 flights leave an hour or more late, so Alaska wasn't stranding people for half a day. It was a steady drip of small delays. The average Alaska departure left about eight minutes behind schedule, compared with under four minutes on Delta, and those minutes added up as the day went on.
Afternoons and evenings were the weak spot. Alaska got 88% of its 6 a.m. to 9 a.m. flights out on time, but from 3 p.m. to 9 p.m. that fell to about seven in 10. Delta's evening flights held up much better, with more than nine in 10 leaving on time between 6 p.m. and 9 p.m. Alaska also had a rough Friday and Monday, when only about seven in 10 of its flights left on time.
Hawaii was hard on everyone. Flights from Seattle to Honolulu were the least punctual route for Alaska, arriving on time only about half the time, and Delta wasn't much better at 57%. If you're headed to the islands, pack your patience along with the sunscreen.
Alaska's Home-Field Advantage
Alaska does have one edge that comes with owning the place. Its planes spent less time driving between the gate and the runway, which pilots call taxiing. The typical Alaska flight took about 19 minutes from pushback to takeoff, compared with about 22 minutes on Delta. It's not much, but it's the kind of thing you notice when you're the one staring out the window at the rain.
Why the Rivalry Matters
Alaska and Delta used to be partners. Until 2017, they shared flights and let travelers earn miles on each other. That fell apart as Delta built Seattle into its own gateway to Asia, and the two have been competing head-on ever since. The fight got bigger when Alaska bought Hawaiian Airlines and its widebody planes, which let Alaska start flying from Seattle to Asia and Europe. I covered how that's playing out in the battle over Seattle to Tokyo flights.
It isn't slowing down. Alaska now flies from Seattle to Tokyo, Seoul, Reykjavik, London and Rome. Paris and Athens are coming in 2027. Delta, which still has about twice as many long-haul seats out of Seattle, is adding a daily flight to Tokyo's Narita airport next March. For anyone flying out of Seattle, two airlines fighting this hard usually means more choice and better fares. On this week's numbers, it also means the newcomer is running the tighter operation.
What to Book
If being on time matters most, Delta was the safer pick out of Seattle this week. If you're loyal to Alaska, and plenty of Seattle travelers are, take the morning flights when you can. That's when Alaska ran nearly as well as Delta. Alaska's own busiest route isn't even in Seattle, which says a lot about how far the airline has grown beyond its hometown.
For as long as I've known Seattle, Alaska has been the heart of Sea-Tac. But Delta has been creeping in over the last few years, and with Alaska expanding just as fast, this is a rivalry I'll be watching closely.
A week is a snapshot, not a final verdict, and Seattle's winter weather can shuffle the order fast. These numbers cover flights Alaska and Delta operate on their own planes, not the smaller regional planes flown by Alaska's sister airline Horizon or partners like SkyWest, and they don't include canceled flights. I ran the same test on United and American at Chicago O'Hare, where the gap was even bigger. Alaska also finished near the top on flights between New York and Los Angeles.
