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Flight Reliability

UA 4506 · United Airlines

St. Louis → Washington (STL–IAD)94% of its flights flew this route. The rest (IAD–CVG) are included in these numbers.

86
Pretty Reliable
WanderNerd Reliability Score
79%
Arrive within 15 minutes
7 min
Average arrival delay
0.3%
Cancelled
12 min early
Median arrival delay

Based on 376 historical flights. Data through May 2026.

What the data says

Morning flights do better here.

UA 4506 departing between 6–9 AM arrived on time 79% of the time, versus 71% between 12–3 PM.

Saturdays have been rough.

UA 4506 arrived on time 90% of the time on Wednesdays and just 71% on Saturdays. That gap is worth planning around.

A bit ahead of the STL–IAD route.

UA 4506 arrived on time 79% of the time, versus 74% across the STL–IAD route.

It basically never cancels.

Out of 376 scheduled flights, only 0.3% were cancelled.

The breakdown

On-time by weekday
  • Mon73%(55 flights)
  • Tue82%(51 flights)
  • Wed90%(51 flights)
  • Thu75%(56 flights)
  • Fri77%(56 flights)
  • Sat71%(51 flights)
  • Sun84%(55 flights)
On-time by departure window
  • 6–9 AM79%(351 flights)
  • 12–3 PM71%(24 flights)
On-time trend by month
81%
May

Jun 63% → May 81% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202563%30
July 202581%31
August 202587%31
September 202589%28
October 202575%20
November 202590%30
December 202574%31
January 202673%30
February 202675%28
March 202676%55
April 202680%30
May 202681%31
Departures on time
78%
Diverted
0%
Flights flown
375
Months covered
12

Same route, other flights

Keep nerding

Based on 376 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.