Flight Reliability
AS 489 · Alaska Airlines
Seattle → Ontario (SEA–ONT)99% of its flights flew this route. The rest (AUS–SEA) are included in these numbers.
- 73%
- Arrive within 15 minutes
- 6 min
- Average arrival delay
- 0.7%
- Cancelled
- 1 min early
- Median arrival delay
Based on 145 historical flights. Data through May 2026.
What the data says
Tuesdays have been rough.
AS 489 arrived on time 85% of the time on Mondays and just 50% on Tuesdays. That gap is worth planning around.
Lagging the SEA–ONT route.
AS 489 arrived on time 73% of the time, versus 83% across the SEA–ONT route.
Lagging the Alaska Airlines network.
AS 489 arrived on time 73% of the time, versus 80% across the Alaska Airlines network.
Ticking up lately.
AS 489 arrived on time 75% of the time over the last three months in the data, compared with 70% in the three months before that.
The breakdown
- Mon85%(26 flights)
- Tue50%(14 flights)
- Wed64%(14 flights)
- Thu80%(25 flights)
- Fri63%(24 flights)
- Sat79%(14 flights)
- Sun78%(27 flights)
- 3–6 PM—(1 flights)
- 6–9 PM74%(31 flights)
- 9 PM–12 AM73%(112 flights)
Nov 70% → May 68% on time
| Month | On-time percentage | Flights |
|---|---|---|
| November 2025 | 70% | 20 |
| December 2025 | 55% | 22 |
| January 2026 | 85% | 20 |
| March 2026 | 80% | 15 |
| April 2026 | 77% | 30 |
| May 2026 | 68% | 28 |
- Departures on time
- 76%
- Diverted
- 0%
- Flights flown
- 144
- Months covered
- 8
Same route, other flights
Keep nerding
Based on 145 historical flights, because apparently we checked. Historical flight data: U.S. Bureau of Transportation Statistics, June 2025 – May 2026. Data through May 2026. How we calculate this.