Alaska Airlines SEA to ONT on-time performance
Alaska Airlines nonstop flights from Seattle to Ontario · Aug 2025 – Jul 2026
On-time arrivals
77%
arrived < 15 min late
Cancelled
1.5%
19 flights
Avg arrival delay
12 min
45 min when late
Rank on route
#4 of 4
route average 83% on time
Key facts
- Alaska Airlines flights on SEA to ONT arrived on time 77% of the time in Aug 2025 – Jul 2026.
- 1.5% were cancelled, and 5% arrived an hour or more late.
- That ranks #4 of 4 airlines on this route, which averaged 83% on time overall.
- The largest source of delay minutes was airline (crew, maintenance, cleaning, fueling) (46%).
On-time trend by month
Why this airline's flights were late
- Airline (crew, maintenance, cleaning, fueling)46%
- Late-arriving aircraft35%
- Air traffic control & airport congestion17%
- Extreme weather1%
- Security0%
Other airlines on SEA to ONT
- SkyWest Airlines89% on time · 7 min avg delay
- Frontier Airlines84% on time · 12 min avg delay
- Delta Air Lines93% on time · 3 min avg delay
Full SEA to ONT comparison →
Alaska Airlines on-time record across all routes →
1,259 Alaska Airlines flights tracked on this route; 19 cancelled, 0 diverted.
Data: U.S. DOT Bureau of Transportation Statistics, Aug 2025 – Jul 2026 (12 months). Latest month published by BTS: July 2026. How we calculate this.