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Flight Reliability

UA 1221 · United Airlines

This number covered several routes in this period.

One number, several routes.

Airlines reuse flight numbers, and UA 1221 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

85%
Arrive within 15 minutes
4 min
Average arrival delay
0.6%
Cancelled
10 min early
Median arrival delay

Based on 481 historical flights. Data through May 2026.

The breakdown

On-time by weekday
  • Mon81%(70 flights)
  • Tue83%(60 flights)
  • Wed79%(66 flights)
  • Thu91%(76 flights)
  • Fri89%(72 flights)
  • Sat83%(59 flights)
  • Sun88%(75 flights)
On-time by departure window
  • 6–9 AM91%(305 flights)
  • 9 AM–12 PM89%(37 flights)
  • 12–3 PM—(2 flights)
  • 3–6 PM100%(15 flights)
  • 6–9 PM68%(101 flights)
  • 9 PM–12 AM72%(18 flights)
On-time trend by month
93%
May

Jun 78% → May 93% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202578%55
July 202588%48
August 202584%38
September 202595%43
October 202587%31
November 202593%29
December 202576%58
January 202678%40
February 202686%28
March 202685%33
April 202687%31
May 202693%44
Departures on time
85%
Diverted
0%
Flights flown
478
Months covered
12

Keep nerding

Based on 481 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.