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Flight Reliability

UA 4391 · United Airlines

This number covered several routes in this period.

One number, several routes.

Airlines reuse flight numbers, and UA 4391 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
20 min
Average arrival delay
4.9%
Cancelled
2 min early
Median arrival delay

Based on 365 historical flights. Data through May 2026.

The breakdown

On-time by weekday
  • Mon58%(48 flights)
  • Tue72%(46 flights)
  • Wed61%(51 flights)
  • Thu63%(49 flights)
  • Fri60%(50 flights)
  • Sat72%(53 flights)
  • Sun77%(47 flights)
On-time by departure window
  • 6–9 AM97%(35 flights)
  • 9 AM–12 PM—(4 flights)
  • 3–6 PM—(1 flights)
  • 6–9 PM62%(300 flights)
  • 9 PM–12 AM—(4 flights)
On-time trend by month
72%
May

Jun 53% → May 72% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202553%30
July 202560%30
August 202575%28
September 202596%28
October 202574%31
November 202572%25
December 202561%31
January 202655%33
February 202661%31
March 202661%28
April 202654%24
May 202672%25
Departures on time
70%
Diverted
0.8%
Flights flown
344
Months covered
12

Keep nerding

Based on 365 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.