PlainFlights

ONT vs SEA - Airport Comparison

Select two airports to compare on-time performance, delays, cancellations, and top routes using U.S. Department of Transportation Bureau of Transportation Statistics (BTS) data (2020–2025) across all 50 states. See our methodology for how metrics are computed.

Airport A
ONT

Ontario, CA

Ontario, California

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Airport B
SEA

Seattle, WA

Seattle, Washington

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Key Performance Metrics

BTS on-time performance data, 2020–2025 cumulative.

Metric ONT SEA
On-Time Rate (higher is better) 82.3% 83.1%
Avg Delay (lower is better) 67.3 min 63.4 min
Delay Rate (lower is better) 17.7% 16.9%
Cancellation Rate (lower is better) 0.92% 0.73%
Total Flights 272,856 1,871,155
Delayed Flights 48,267 315,819
Cancelled Flights 2,519 13,720
Top Delay Cause Late Aircraft Carrier

✓ / ▲ indicates the more favorable value. Data: BTS On-Time Performance, 2020–2025.

Delay Cause Breakdown

ONT - Ontario, CA

Late Aircraft 43.6%
Carrier 35.3%
NAS 17.7%
Weather 3.3%
Security 0.1%

SEA - Seattle, WA

Carrier 44.3%
Late Aircraft 28.6%
NAS 21.0%
Weather 5.8%
Security 0.3%

Top Routes

Top routes from ONT

Route Flights On-Time
PHX → ONT
Ontario
16,938 81.2%
ONT → PHX
Phoenix
16,845 85%
DEN → ONT
Ontario
14,378 75.1%
ONT → DEN
Denver
14,321 84%
SEA → ONT
Ontario
12,866 83.5%
ONT → SEA
Seattle
12,860 87.1%

Top routes from SEA

Route Flights On-Time
SEA → LAX
Los Angeles
41,859 84%
LAX → SEA
Seattle
41,819 86.2%
SEA → ANC
Anchorage
41,143 77.5%
ANC → SEA
Seattle
41,064 85.8%
PHX → SEA
Seattle
38,561 84.3%
SEA → PHX
Phoenix
38,549 82.3%

Source: Bureau of Transportation Statistics (BTS), On-Time Performance Data (2020–2025) Bureau of Transportation Statistics (BTS), On-Time Performance Data (2020–2025) On-time rates exclude cancelled and diverted flights. PlainFlights is not affiliated with BTS or the DOT

Every figure on PlainFlights is rendered directly from BTS On-Time Performance data, no number is typed in by an editor. This tool queries live on-time, delay, and cancellation figures for the two selected airports from the dataset. See our editorial standards & corrections policy, the methodology behind these numbers, or report a data error.