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Flight Reliability

UA 3990 · United Airlines

Houston → Louisville (IAH–SDF)82% of its flights flew this route. The rest (BNA–IAH, AUS–IAD) are included in these numbers.

92
Nerd Approved
WanderNerd Reliability Score
87%
Arrive within 15 minutes
2 min early
Average arrival delay
0.4%
Cancelled
9 min early
Median arrival delay

Based on 246 historical flights. Data through May 2026.

What the data says

The 12–3 PM departure wins.

UA 3990 departing between 12–3 PM arrived on time 97% of the time, versus 83% between 6–9 AM.

Thursdays have been rough.

UA 3990 arrived on time 100% of the time on Saturdays and just 77% on Thursdays. That gap is worth planning around.

A bit ahead of the IAH–SDF route.

UA 3990 arrived on time 87% of the time, versus 81% across the IAH–SDF route.

Better than the United Airlines network average.

UA 3990 arrived on time 87% of the time, versus 79% across the United Airlines network.

The breakdown

On-time by weekday
  • Mon89%(35 flights)
  • Tue80%(35 flights)
  • Wed85%(34 flights)
  • Thu77%(34 flights)
  • Fri86%(36 flights)
  • Sat100%(36 flights)
  • Sun94%(34 flights)
On-time by departure window
  • 6–9 AM83%(47 flights)
  • 9 AM–12 PM87%(157 flights)
  • 12–3 PM97%(37 flights)
  • 3–6 PM—(2 flights)
  • 6–9 PM—(1 flights)
On-time trend by month
81%
May

Oct 94% → May 81% on time

On-time arrival percentage by month
MonthOn-time percentageFlights
October 202594%31
November 2025100%29
December 202583%30
January 202679%29
February 202693%27
March 202677%31
April 202690%30
May 202681%31
Departures on time
89%
Diverted
0.4%
Flights flown
244
Months covered
9

Same route, other flights

Keep nerding

Based on 246 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.