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Flight Reliability

UA 4738 · United Airlines

BIS → Denver (BIS–DEN)99% of its flights flew this route. The rest (DEN–OMA, GRR–ORD) are included in these numbers.

93
Nerd Approved
WanderNerd Reliability Score
88%
Arrive within 15 minutes
3 min early
Average arrival delay
0.5%
Cancelled
19 min early
Median arrival delay

Based on 365 historical flights. Data through May 2026.

What the data says

Mornings have a slight edge.

Departures between 6–9 AM arrived on time 90% of the time, against 86% between 3–6 AM.

Skip Saturday if you can.

UA 4738 arrived on time 94% of the time on Wednesdays. On Saturdays: 85%.

Better than the BIS–DEN route average.

UA 4738 arrived on time 88% of the time, versus 78% across the BIS–DEN route.

Better than the United Airlines network average.

UA 4738 arrived on time 88% of the time, versus 79% across the United Airlines network.

The breakdown

On-time by weekday
  • Mon90%(50 flights)
  • Tue89%(52 flights)
  • Wed94%(52 flights)
  • Thu85%(52 flights)
  • Fri89%(52 flights)
  • Sat85%(52 flights)
  • Sun87%(52 flights)
On-time by departure window
  • 3–6 AM86%(150 flights)
  • 6–9 AM90%(209 flights)
  • 9 AM–12 PM—(1 flights)
  • 12–3 PM—(1 flights)
  • 3–6 PM—(1 flights)
On-time trend by month
97%
May

Jun 87% → May 97% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
June 202587%30
July 202590%31
August 202587%31
September 202593%30
October 202590%31
November 202590%30
December 202577%31
January 202687%31
February 202689%28
March 202686%29
April 202683%29
May 202697%31
Departures on time
88%
Diverted
0.3%
Flights flown
362
Months covered
12

Same route, other flights

Keep nerding

Based on 365 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.