Carrier performance at one airport
UA→IAH
United Airlines at George Bush Intercontinental
- Departures
- 73,829
- Period
- June 2025 to May 2026
- Routes
- 25
- Rank here
- #2 of 10
United Airlines at Houston lands a B+, 2 points better than the national rate of 77.4%. About one flight in five arrive 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 73,829 flights, of which Delta Air Lines flew 8,344 at 80.3% on time.
Measured against the airport rather than the country, United Airlines runs about a point ahead of the 78.0% weighted average across all carriers at IAH. That is the comparison worth making: every operator here works the same runways, the same airspace and the same weather.
Key figures
On time
79.3%
73,059 completed departures
Avg delay
67 min
Across delayed flights only
Cancelled
0.80%
At IAH, this carrier only
Rank here
#2
Of 10 carriers clearing the floor at IAH
These figures cover 74,000 flights between June 2025 and May 2026. The median arrival is 6 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
Against the competition
Every carrier at IAH, ranked
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 80.3% of the time; JetBlue Airways manages 60.3%. Sample sizes sit next to every figure, because a two-point gap across 493 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 8,344 | 80.3% | 86 min | 1.89% | B |
| United Airlines (this page) | 73,829 | 79.3% | 67 min | 0.80% | B+ |
| Alaska Airlines | 1,208 | 77.2% | 56 min | 1.16% | B |
| American Airlines | 7,653 | 76.8% | 132 min | 2.61% | B |
| SkyWest Airlines | 14,441 | 76.2% | 94 min | 1.45% | B |
| Envoy Air | 1,489 | 76.1% | 80 min | 2.42% | B |
| Republic Airways | 874 | 74.2% | 74 min | 3.89% | C− |
| Spirit Airlines | 6,056 | 74.0% | 74 min | 2.77% | C |
| Frontier Airlines | 4,514 | 69.1% | 89 min | 1.71% | C |
| JetBlue Airways | 493 | 60.3% | 80 min | 2.23% | D |
Republic Airways cancels 3.9% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.
Route by route
Where United Airlines flies from IAH
United Airlines operates 25 routes out of IAH with enough volume to report. Route records inside one carrier at one airport still spread widely, because a short shuttle and a transcontinental have very different exposure to a late inbound.
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| IAH to ORD · Chicago | 3,981 | 78.2% | 66 min | 0.73% | B+ |
| IAH to DEN · Denver | 3,854 | 81.2% | 70 min | 0.31% | B+ |
| IAH to SFO · San Francisco | 3,595 | 79.2% | 71 min | 0.53% | B+ |
| IAH to EWR · Newark | 3,473 | 74.0% | 75 min | 1.58% | C |
| IAH to LAX · Los Angeles | 3,394 | 83.7% | 63 min | 0.41% | B+ |
| IAH to MSY · New Orleans | 2,798 | 82.6% | 66 min | 0.43% | B+ |
| IAH to LAS · Las Vegas | 2,607 | 83.6% | 60 min | 0.50% | B+ |
| IAH to AUS · Austin | 2,579 | 78.5% | 68 min | 1.05% | B |
| IAH to MCO · Orlando | 2,480 | 84.5% | 76 min | 0.81% | B+ |
| IAH to DCA · Washington | 2,409 | 75.4% | 69 min | 0.95% | B+ |
| IAH to DFW · Dallas-Fort Worth | 2,389 | 75.4% | 74 min | 1.93% | B |
| IAH to LGA · New York | 2,378 | 70.6% | 76 min | 1.77% | C |
| IAH to SAT · San Antonio | 2,363 | 82.7% | 63 min | 0.85% | B+ |
| IAH to IAD · Washington | 1,862 | 79.6% | 62 min | 0.59% | B+ |
| IAH to FLL · Fort Lauderdale | 1,802 | 85.0% | 66 min | 0.72% | A+ |
| IAH to PHX · Phoenix | 1,791 | 79.5% | 65 min | 0.50% | B+ |
| IAH to SAN · San Diego | 1,692 | 80.4% | 62 min | 0.47% | B+ |
| IAH to BOS · Boston | 1,575 | 75.6% | 74 min | 1.21% | B |
| IAH to MIA · Miami | 1,485 | 79.7% | 60 min | 0.54% | B+ |
| IAH to TPA · Tampa | 1,376 | 83.6% | 69 min | 0.44% | B+ |
| IAH to SEA · Seattle | 1,252 | 76.1% | 61 min | 0.72% | B+ |
| IAH to ATL · Atlanta | 1,236 | 81.9% | 71 min | 0.81% | B+ |
| IAH to SNA · Santa Ana | 1,094 | 87.5% | 56 min | 0.18% | A+ |
| IAH to BNA · Nashville | 994 | 73.9% | 65 min | 0.60% | C+ |
| IAH to SLC · Salt Lake City | 886 | 83.0% | 63 min | 0.90% | B+ |
Departure window
Best time of day for this operation
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 20 points, against 20 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am9,969 flights92.0%
- 8am–11am11,031 flights84.9%
- 11am–2pm11,423 flights81.4%
- 2pm–5pm12,668 flights76.7%
- 5pm–8pm12,803 flights71.6%
- 8pm–5am15,935 flights73.9%
Scale runs 65% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 92.0% of the time, against 71.6% for the evening window. That is 20 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on.
Across the year
Seasonal pattern
June is the worst month at 65.4% on time, 23 points below January, the best at 88.1%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck.
Delay causes
What holds this operation up
- 37%Late-arriving aircraft
- 29%Carrier
- 27%National Airspace System
- 8%Extreme weather
- 0%Security
37% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. That is a cascade, and cascades start small and grow through the day. Across 1.01 million reported delay minutes here, that single category outweighs weather by 5 to one. It is the strongest argument for booking the first departure of the morning, when the aircraft has been sitting at the gate overnight with nothing to inherit.
Cancellations are rare at 0.80%, below the national 1.80% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
7.6% of arrivals land an hour or more late, close to the national 8.2%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route are the about an hour kind, which a normal layover absorbs.
73,829 flights sit behind these numbers, which is a large enough sample that the headline rate is not moving on noise. Where a sub-group falls below 30 flights the site shows a dash instead of a percentage.
Put together: the calendar is the biggest lever here, not the carrier or the hour. January runs 88.1% on time and June 65.4%, a swing of 23 points. If the dates move at all, move them out of June before you think about anything else.
Common questions
United Airlines at IAH
How often is United Airlines at IAH delayed?
About one flight in five arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 20.7% of the 73,829 flights in this analysis, against 22.6% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on United Airlines at IAH?
Delta Air Lines leads at 80.3% on time across 8,344 flights. JetBlue Airways is at the other end on 60.3%, a gap of 20 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on United Airlines at IAH?
The 5am–8am departure window is the strongest at 92.0% on time. The 5pm–8pm window is the weakest at 71.6%, 20 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are June delays on United Airlines at IAH?
June is the weakest month at 65.4% on time, compared with 88.1% in January. Across the year that is 23 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
Source: US DOT Bureau of Transportation Statistics, on-time performance data, June 2025 to May 2026. Updated monthly. How this data is collected.