Flight profile · Alaska Airlines
AS429
Seattle (SEA) to Chicago (ORD) · scheduled 10:50 AM – 4:57 PM
How AS429 performs
330 operations, 2025-03-19 to 2026-06-30.
AS429 arrived on time 56.2% of the time, against 77.6% for all SEA → ORD flights — this specific departure is 21.4 percentage points worse than the route as a whole. Against Alaska Airlines’s own flights on this route it is 18.5 points worse.
Source: US DOT Bureau of Transportation Statistics · 330 operations between 2025-03-19 to 2026-06-30
Against the rest of the route
| On time | Cancelled | Median delay | Severe | Flights | |
|---|---|---|---|---|---|
| AS429 | 56.2% | 1.82% | 9 min | 10.2% | 330 |
| Alaska Airlines on SEA → ORD | 74.7% | 0.71% | -2 min | 5.7% | 5,470 |
| All SEA → ORD flights | 77.6% | 0.93% | -5 min | 6.7% | 15,693 |
Source: FlyerIntel analysis of US DOT BTS data · 2025-03-19 to 2026-06-30
Other routes AS429 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 |
|---|---|---|---|
| ORD→SEA Chicago to Seattle | 2026-05-13 – 2026-06-09 | 28 | — |
| SEA→BOI Seattle to Boise | 2026-03-19 – 2026-04-21 | 34 | — |
| MCI→SEA Kansas City to Seattle | 2026-03-14 – 2026-03-14 | 1 | — |
| SEA→LAS Seattle to Las Vegas | 2026-01-07 – 2026-02-11 | 31 | — |
| PIT→SEA Pittsburgh to Seattle | 2024-08-23 – 2024-09-30 | 18 | — |
| SEA→SFO Seattle to San Francisco | 2024-08-20 – 2024-08-20 | 1 | — |
| BWI→SEA Baltimore to Seattle | 2024-06-13 – 2024-06-13 | 1 | — |
| BNA→SEA Nashville to Seattle | 2023-07-01 – 2023-11-16 | 118 | 92.4% |
Because the same number has served different journeys, the statistics above describe only the route AS429 currently operates. Blending them would produce an average of two different flights.
Why AS429 runs late
Where US DOT attributed the delay minutes on this flight.
airspace and airport capacity, including weather-driven flow control
the inbound aircraft was late, so this flight started late
crew, maintenance, boarding, fuelling — within the carrier’s control
weather severe enough to stop this flight specifically
Share of the delay minutes US DOT attributed to each cause for AS429 on SEA → ORD. 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 SEA → ORD
Same airports, same journey — and not the same odds of arriving on time.
| Flight | Airline | On time | Median arrival | Operations |
|---|---|---|---|---|
| UA747 | United Airlines | 84.8% | 11 min early | 1,093 |
| DL2055 | Delta Air Lines | 83.9% | 7 min early | 681 |
| AS538 | Alaska Airlines | 80.4% | 3 min early | 1,047 |
| AS328 | Alaska Airlines | 78.9% | 5 min early | 807 |
| DL2108 | Delta Air Lines | 76.9% | 5 min early | 712 |
| AS410 | Alaska Airlines | 61.1% | 6 min late | 869 |
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 330 records of AS429 operating SEA → ORD, 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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