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Flight Reliability

UA 4599 · United Airlines

Chicago → Birmingham (ORD–BHM)96% of its flights flew this route. The rest (ORD–ICT, BTV–IAD) are included in these numbers.

35
Bring Snacks
WanderNerd Reliability Score
59%
Arrive within 15 minutes
36 min
Average arrival delay
4.1%
Cancelled
5 min
Median arrival delay

Based on 338 historical flights. Data through May 2026.

What the data says

Monday is the weak spot.

UA 4599 arrived on time 67% of the time on Saturdays. On Mondays: 53%.

Lagging the ORD–BHM route.

UA 4599 arrived on time 59% of the time, versus 73% across the ORD–BHM route.

Well behind the United Airlines network.

UA 4599 arrived on time 59% of the time, versus 79% across the United Airlines network.

Keep a backup plan handy.

UA 4599 was cancelled 4.1% of the time. Typical for U.S. flights is around 1–2%.

The breakdown

On-time by weekday
  • Mon53%(45 flights)
  • Tue66%(47 flights)
  • Wed58%(48 flights)
  • Thu57%(46 flights)
  • Fri57%(47 flights)
  • Sat67%(42 flights)
  • Sun55%(47 flights)
On-time by departure window
  • 3–6 PM—(1 flights)
  • 6–9 PM59%(311 flights)
  • 9 PM–12 AM60%(10 flights)
On-time trend by month
58%
May

Jun 70% → May 58% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202570%30
July 202531%29
August 202560%30
September 202570%30
October 202580%30
November 202562%26
December 202540%30
January 202652%21
February 202643%14
March 202660%25
April 202673%26
May 202658%31
Departures on time
60%
Diverted
0.6%
Flights flown
322
Months covered
12

Same route, other flights

Keep nerding

Based on 338 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.