Delta Air Lines is the most reliable airline on the SEA to DCA route with a 92% on-time rate, compared to Alaska Airlines at 78%. Based on 509 flights tracked.
Source: Bureau of Transportation Statistics. Updated October 2026.Best Airline: SEA to DCA
Seattle to Washington — airline reliability comparison
On-Time Rate by Airline
Delta Air Lines92%
Alaska Airlines78%
SEA to DCA Airline Comparison
| Airline | On-Time % | Cancel % | Avg Delay | Flights |
|---|---|---|---|---|
| Delta Air LinesDLBest | 92% | 2.3% | 83m | 509 |
| Alaska AirlinesASWorst | 78% | 0.6% | 49m | 2,612 |
Route Overview
80%
Overall On-Time
53m
Avg Delay
0.9%
Cancel Rate
3,121
Total Flights
Flying out of SEA? We'll brief you.
Delays, TSA, weather, gates — we'll let you know if something matters.
Data last updated October 2026. Source: Bureau of Transportation Statistics.