Route Reliability

Route reliability

Denver (DEN) to Houston (IAH): which airline is most on time?

On-time arrivals, cancellations and long delays for every airline that reported nonstop flights from Denver, CO (DEN) to Houston, TX (IAH), September 2025 to August 2026.

Historical performance Official DOT data through August 2026 · Not live flight status

Denver, COHouston, TX

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Three-letter airport codes, nonstop U.S. domestic flights. One direction at a time.

Route at a glance · September 2025 to August 2026

DEN to IAH

Denver, CO to Houston, TX

On time
79.3%vs 75.6% U.S. average Better than average
Cancelled
0.3%vs 1.9% U.S. average Better than average
60+ min late
6.8%vs 8.1% U.S. average Better than average
Scheduled flights
4,728in 12 months2 airlines
Most reliable airline
United Airlines79.4% on time · 3,894 flights

On time more often than the U.S. average, with fewer cancellations.

Compared with all U.S. flights, September 2025 to August 2026. “About average” means within 1.5 points for on time, 0.3 for cancelled and 1 for 60+ minutes late.

Airlines on this route

Ranked by on-time arrival

Airlines from DEN to IAH, September 2025 to August 2026. Rates are shares of all scheduled flights.
Airline On time Cancelled 60+ min late Avg delay when late Diverted Flights
1. United Airlines Most reliable 79.4% 0.3% 6.8% 63 min 0.2% 3,894
2. Frontier Airlines 78.8% 0.5% 7.1% 58 min 0.1% 834

On time = arrived within 15 minutes of schedule. Avg delay when late = average arrival delay of flights 15+ minutes late. "Most reliable" needs at least 300 flights in 12 months. Tap a heading to sort.

What this means

United Airlines has the strongest record on this route.

  • United Airlines had the best on-time record from Denver (DEN) to Houston (IAH): 79.4% of its 3,894 scheduled flights arrived within 15 minutes of schedule, compared with 78.8% for Frontier Airlines. The gap is small, so treat the airlines as roughly equal on punctuality.
  • 0.3% of flights on this route were cancelled, 1.6 points lower than the U.S. average of 1.9%.
  • 6.8% of flights, about 1 in 15, arrived an hour or more late. When a flight was late (15+ minutes), the average arrival delay was 62 min.
  • Overall, 79.3% of flights on this route arrived on time, 3.7 points higher than the U.S. average of 75.6%.
  • Over the last 3 years, October was the most reliable month on this route (84.4% on time) and July the least reliable (63.2%).
  • Cancellations peaked in January, when 3.5% of flights were cancelled.
  • Flights scheduled to depart before 6 am were the most punctual (95.8% on time); flights scheduled to depart 6 pm to 7 pm were the least (68.9%).
  • In the other direction, Houston (IAH) to Denver (DEN), 82.5% of flights were on time and 0.4% were cancelled. Compare airlines IAH to DEN.

Best and worst months to fly DEN to IAH

Jan 74.9%
Feb 80.7%
Mar 79.4%
Apr 78.7%
May 70.6%
Jun 68.1%
Jul 63.2%
Aug 69.9%
Sep 83.0%
Oct 84.4%
Nov 81.5%
Dec 82.2%
Share of scheduled flights on time 12-month average 79.3%
All airlines combined, by calendar month, September 2023 to August 2026 (3 years pooled). Scale starts at zero.
Show as table
PeriodOn timeFlights
January 74.9% 1,181
February 80.7% 1,073
March 79.4% 1,225
April 78.7% 1,157
May 70.6% 1,257
June 68.1% 1,278
July 63.2% 1,314
August 69.9% 1,232
September 83.0% 1,215
October 84.4% 1,209
November 81.5% 1,128
December 82.2% 1,195
Best and worst calendar month by airline, September 2023 to August 2026.
AirlineBest monthWorst month
United Airlines October (86.2%) July (62.7%)
Frontier Airlines February (85.0%) July (63.4%)

Month by month, last 12 months

Sep 81.2%
Oct 85.9%
Nov 79.8%
Dec 82.1%
Jan 86.7%
Feb 85.6%
Mar 77.8%
Apr 86.1%
May 81.6%
Jun 68.4%
Jul 71.8%
Aug 68.3%
Share of scheduled flights on time U.S. average 75.6%
All airlines combined, September 2025 to August 2026. Scale starts at zero.
Show as table
PeriodOn timeFlights
Sep 2025 81.2% 382
Oct 2025 85.9% 398
Nov 2025 79.8% 357
Dec 2025 82.1% 391
Jan 2026 86.7% 384
Feb 2026 85.6% 347
Mar 2026 77.8% 406
Apr 2026 86.1% 360
May 2026 81.6% 412
Jun 2026 68.4% 431
Jul 2026 71.8% 444
Aug 2026 68.3% 416

Best and worst departure times

<6a 95.8%
6a 90.0%
7a 88.8%
8a Insufficient sample
9a 81.9%
10a 83.1%
11a 80.5%
12p Insufficient sample
1p 71.2%
2p Insufficient sample
3p 77.3%
4p 78.5%
5p 73.2%
6p 68.9%
7p 75.5%
8p 77.1%
9p 71.4%
11p Insufficient sample
Share of scheduled flights on time
By scheduled local departure hour at DEN, September 2025 to August 2026. Hours with no scheduled flights are omitted. Scale starts at zero.
Show as table
PeriodOn timeFlights
Departing before 6 am 95.8% 382
Departing 6 am to 7 am 90.0% 60
Departing 7 am to 8 am 88.8% 561
Departing 8 am to 9 am Insufficient sample 5
Departing 9 am to 10 am 81.9% 149
Departing 10 am to 11 am 83.1% 242
Departing 11 am to noon 80.5% 384
Departing noon to 1 pm Insufficient sample 23
Departing 1 pm to 2 pm 71.2% 365
Departing 2 pm to 3 pm Insufficient sample 7
Departing 3 pm to 4 pm 77.3% 392
Departing 4 pm to 5 pm 78.5% 339
Departing 5 pm to 6 pm 73.2% 447
Departing 6 pm to 7 pm 68.9% 212
Departing 7 pm to 8 pm 75.5% 404
Departing 8 pm to 9 pm 77.1% 401
Departing 9 pm to 10 pm 71.4% 353
Departing 11 pm to midnight Insufficient sample 2
Woman at an airport window watching a plane take off
Photo: Depositphotos (licensed stock, illustrative only). Credits

Sources & data dates

Source
U.S. DOT Bureau of Transportation Statistics, Reporting Carrier On-Time Performance (1987-present)
Period
September 2025 to August 2026 (12 months); month-of-year patterns September 2023 to August 2026
Data through
August 2026
Processed
2026-11-03
Scope
Nonstop scheduled flights from Denver, CO (DEN) to Houston, TX (IAH), one direction. Airlines that report to the DOT only.
Method
Rates use all scheduled flights as the denominator; cancelled and diverted flights count as not on time. Figures based on fewer than 50 scheduled flights are suppressed. Full methodology.

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