Miami to Denver — airline reliability comparison
Spirit Airlines is the most reliable airline on the MIA to DEN route with a 90% on-time rate, compared to Southwest Airlines at 66%. Based on 335 flights tracked.
This route involves weather-prone airports and high-congestion airports, which can affect reliability regardless of airline.
Source: Bureau of Transportation Statistics. Updated October 2026.| Airline | On-Time % | Cancel % | Avg Delay | Flights |
|---|---|---|---|---|
| Spirit AirlinesNKBest | 90% | 0.6% | 71m | 335 |
| United AirlinesUA | 80% | 0.6% | 84m | 3,076 |
| Frontier AirlinesF9 | 77% | 1.1% | 85m | 1,359 |
| American AirlinesAA | 72% | 0.8% | 74m | 3,071 |
| Southwest AirlinesWNWorst | 66% | 0.6% | 58m | 966 |
Delays, TSA, weather, gates — we'll let you know if something matters.
Data last updated October 2026. Source: Bureau of Transportation Statistics.