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Flight Reliability

UA 1239 · United Airlines

This number covered several routes in this period.

One number, several routes.

Airlines reuse flight numbers, and UA 1239 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

79%
Arrive within 15 minutes
6 min
Average arrival delay
0.7%
Cancelled
7 min early
Median arrival delay

Based on 597 historical flights. Data through May 2026.

The breakdown

On-time by weekday
  • Mon75%(85 flights)
  • Tue76%(80 flights)
  • Wed79%(80 flights)
  • Thu87%(91 flights)
  • Fri79%(87 flights)
  • Sat79%(82 flights)
  • Sun73%(86 flights)
On-time by departure window
  • 6–9 AM87%(86 flights)
  • 9 AM–12 PM83%(208 flights)
  • 12–3 PM69%(214 flights)
  • 3–6 PM60%(25 flights)
  • 6–9 PM91%(58 flights)
On-time trend by month
80%
May

Jun 66% → May 80% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202566%35
July 202567%51
August 202581%43
September 202570%66
October 202587%91
November 202578%86
December 202573%40
January 202690%31
February 202686%28
March 202676%29
April 202694%31
May 202680%60
Departures on time
83%
Diverted
0.3%
Flights flown
591
Months covered
12

Keep nerding

Based on 597 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.