Which airline is most reliable for SEA (Seattle) to STL (St. Louis)?

The most reliable airline on the SEA to STL route is Alaska Airlines, with an on-time arrival rate of 83%.

How often are flights delayed from SEA to STL?

About 21% of flights from SEA to STL experience delays. 79% arrive on time.

What's the average delay on SEA to STL flights?

When flights from SEA to STL are delayed, the average delay is approximately 43 minutes.

Is a short connection safe after a SEA to STL flight?

With 79% of SEA to STL flights arriving on time and an average delay of 43 minutes when late, a connection under 60 minutes at STL is risky. We recommend at least 75-90 minutes for domestic connections after this route.

SEA → STL

SEA (Seattle) to STL (St. Louis)

SEA (Seattle) to STL (St. Louis) flights arrive on time 79% of the time. The most reliable airline on this route is Alaska Airlines at 83%. The average delay is 43 minutes. Delays on this route are most often caused by the airline (crew, maintenance, or boarding).

Source: Bureau of Transportation Statistics. Updated October 2026.

SEA → STL on-time performance by month

JanFebMarAprMayJunJulAugSepOctNovDec

Worse

Better

This route is on time most of the time. About 79% of flights arrive on schedule.

Delays on this route are most often caused by the airline (crew, maintenance, or boarding).

Accurate?

Alaska Airlines is significantly more reliable on this route at 83% on time vs Southwest Airlines at 59%.

Airline Comparison

Alaska Airlines leads at 83% on time; Southwest Airlines trails at 59%.

Accurate?

Good to know

Departing from SEA

81% on time

Expect ~20 min sitting on the taxiway after your gate pushes back. SEA has long runway queues.

TSA is currently ~27 min. Best time: 4 AM (about 5 min).

More about SEA →

Arriving at STL

80% on time

When flights into STL are late, the average delay is 64 minutes. Build buffer if you have ground plans.

If connecting at STL: TSA is ~30 min right now. Allow at least 60 minutes for a domestic connection.

More about STL →Connection times at STL →

Flight cancelled or delayed?

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Flying out of SEA? We'll brief you.

Delays, TSA, weather, gates — we'll let you know if something matters.

SEA Airport STL Airport

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Data last updated October 2026. Source: Bureau of Transportation Statistics.