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Flight Reliability

UA 4577 · United Airlines

This number covered several routes in this period.

One number, several routes.

Airlines reuse flight numbers, and UA 4577 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

73%
Arrive within 15 minutes
21 min
Average arrival delay
1.6%
Cancelled
6 min early
Median arrival delay

Based on 305 historical flights. Data through May 2026.

The breakdown

On-time by weekday
  • Mon63%(43 flights)
  • Tue74%(42 flights)
  • Wed68%(40 flights)
  • Thu80%(44 flights)
  • Fri77%(43 flights)
  • Sat76%(45 flights)
  • Sun74%(42 flights)
On-time by departure window
  • 9 AM–12 PM69%(125 flights)
  • 12–3 PM82%(109 flights)
  • 3–6 PM82%(17 flights)
  • 6–9 PM58%(31 flights)
  • 9 PM–12 AM65%(17 flights)
On-time trend by month
68%
May

Jul 90% → May 68% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
July 202590%29
August 202587%31
September 202586%29
October 202564%22
November 202554%26
December 202562%13
January 202674%31
February 202678%27
March 202668%28
April 202665%26
May 202668%31
Departures on time
75%
Diverted
0.3%
Flights flown
299
Months covered
12

Keep nerding

Based on 305 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.