United Airlines is the most reliable airline on the IAD to SJU route with a 85% on-time rate, compared to Frontier Airlines at 43%. Based on 1,790 flights tracked.
Source: Bureau of Transportation Statistics. Updated October 2026.Best Airline: IAD to SJU
Washington to San Juan — airline reliability comparison
On-Time Rate by Airline
United Airlines85%
Frontier Airlines43%
IAD to SJU Airline Comparison
| Airline | On-Time % | Cancel % | Avg Delay | Flights |
|---|---|---|---|---|
| United AirlinesUABest | 85% | 0.3% | 50m | 1,790 |
| Frontier AirlinesF9Worst | 43% | 2.6% | 172m | 78 |
Route Overview
82%
Overall On-Time
66m
Avg Delay
0.5%
Cancel Rate
1,894
Total Flights
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Data last updated October 2026. Source: Bureau of Transportation Statistics.