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Flight Reliability

UA 2121 · United Airlines

This number covered several routes in this period.

One number, several routes.

Airlines reuse flight numbers, and UA 2121 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

62%
Arrive within 15 minutes
20 min
Average arrival delay
0.2%
Cancelled
3 min
Median arrival delay

Based on 430 historical flights. Data through May 2026.

The breakdown

On-time by weekday
  • Mon58%(64 flights)
  • Tue64%(58 flights)
  • Wed65%(62 flights)
  • Thu51%(61 flights)
  • Fri58%(60 flights)
  • Sat68%(59 flights)
  • Sun69%(62 flights)
On-time by departure window
  • 6–9 AM14%(52 flights)
  • 9 AM–12 PM63%(49 flights)
  • 12–3 PM71%(127 flights)
  • 3–6 PM72%(87 flights)
  • 6–9 PM65%(111 flights)
On-time trend by month
54%
May

Jun 82% → May 54% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202582%27
July 202539%31
August 202572%18
October 202558%31
November 202597%29
December 202568%31
January 202663%30
February 202671%28
March 202664%36
April 202649%90
May 202654%69
Departures on time
68%
Diverted
0.7%
Flights flown
426
Months covered
12

Keep nerding

Based on 430 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.