Flight profile · Alaska Airlines
AS503
Austin (AUS) to Seattle (SEA) · scheduled 1:36 PM – 3:59 PM
How AS503 performs
535 operations, 2023-07-01 to 2026-06-30.
AS503 arrived on time 86.2% of the time, against 82.6% for all AUS → SEA flights — this specific departure is 3.6 percentage points better than the route as a whole. Against Alaska Airlines’s own flights on this route it is 5.2 points better.
Source: US DOT Bureau of Transportation Statistics · 535 operations between 2023-07-01 to 2026-06-30
Against the rest of the route
| On time | Cancelled | Median delay | Severe | Flights | |
|---|---|---|---|---|---|
| AS503 | 86.2% | 0.75% | -8 min | 4.9% | 535 |
| Alaska Airlines on AUS → SEA | 81.0% | 1.26% | -6 min | 5.3% | 3,504 |
| All AUS → SEA flights | 82.6% | 1.07% | -8 min | 5.6% | 6,186 |
Source: FlyerIntel analysis of US DOT BTS data · 2023-07-01 to 2026-06-30
Other routes AS503 has flown
A flight number is a slot in a schedule, and carriers reassign it. These are the other city pairs this number served in the analysis period.
| Route | Operated | Flights | On time |
|---|---|---|---|
| STL→SEA St. Louis to Seattle | 2025-02-13 – 2025-06-10 | 52 | — |
| SEA→STL Seattle to St. Louis | 2025-02-13 – 2025-03-18 | 30 | — |
| SEA→MKE Seattle to Milwaukee | 2024-12-01 – 2024-12-01 | 1 | — |
| SEA→FLL Seattle to Fort Lauderdale | 2024-11-22 – 2024-11-22 | 1 | — |
| ORD→SEA Chicago to Seattle | 2024-10-26 – 2024-10-26 | 1 | — |
| IND→SEA Indianapolis to Seattle | 2024-05-16 – 2024-06-12 | 28 | — |
Because the same number has served different journeys, the statistics above describe only the route AS503 currently operates. Blending them would produce an average of two different flights.
Why AS503 runs late
Where US DOT attributed the delay minutes on this flight.
the inbound aircraft was late, so this flight started late
crew, maintenance, boarding, fuelling — within the carrier’s control
airspace and airport capacity, including weather-driven flow control
weather severe enough to stop this flight specifically
screening or terminal security incidents
Share of the delay minutes US DOT attributed to each cause for AS503 on AUS → SEA. A single late flight can carry more than one cause, and only delays of fifteen minutes or more are attributed at all.
Other departures on AUS → SEA
Same airports, same journey — and not the same odds of arriving on time.
| Flight | Airline | On time | Median arrival | Operations |
|---|---|---|---|---|
| DL780 | Delta Air Lines | 93.3% | 16 min early | 633 |
| AS595 | Alaska Airlines | 85.4% | 5 min early | 780 |
Every departure listed carries at least 600 operations, so the comparison is between figures that mean something. Schedules change; confirm the departure still operates before booking around this.
Data and methodology
Calculated by FlyerIntel from 535 records of AS503 operating AUS → SEA, published by the US DOT Bureau of Transportation Statistics. A flight counts as delayed when it arrives 15 or more minutes after schedule. Cancelled and diverted flights are excluded from the on-time rate and reported separately. Flight numbers are resolved as carrier plus number plus route, because the same number serves different routes over time.
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