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WanderNerd

Flight Reliability

NK 391 · Spirit Airlines

This number covered several routes in this period.

One number, several routes.

Airlines reuse flight numbers, and NK 391 moved between routes during this period. Numbers below combine all of them, so treat them as background, not a verdict. For a cleaner answer, check the route you are actually flying.

Combined across all its routes

66%
Arrive within 15 minutes
21 min
Average arrival delay
10.3%
Cancelled
5 min
Median arrival delay

Based on 146 historical flights. Data through May 2026.

The breakdown

On-time by weekday
  • Mon81%(16 flights)
  • Tue67%(18 flights)
  • Wed70%(20 flights)
  • Thu52%(21 flights)
  • Fri70%(20 flights)
  • Sat65%(17 flights)
  • Sun63%(19 flights)
On-time by departure window
  • 9 AM–12 PM72%(87 flights)
  • 12–3 PM59%(32 flights)
  • 3–6 PM(4 flights)
  • 6–9 PM(8 flights)
On-time trend by month
41%
Apr

Dec 54% → Apr 41% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
December 202554%26
January 202682%27
February 202682%27
March 202669%26
April 202641%22
Departures on time
73%
Diverted
0%
Flights flown
131
Months covered
6

Based on 146 historical flights, because apparently we checked. Historical flight data: U.S. Bureau of Transportation Statistics, June 2025 – May 2026. Data through May 2026. How we calculate this.