Carrier route record

UAIAH→DTW

United Airlines · Houston to Detroit

Flights: 283
Period: July 2025 to June 2026
Share of route: 13%
Carriers: 5

Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with United Airlines.

United on IAH to DTW sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 7 points worse than the national rate of 77.6%. The late ones land about an hour behind schedule. That rests on 283 flights. The strongest carrier on the route with a full sample, Delta Air Lines, flew 1,322 at 82.3% on time.

The national on-time rate over the same period is 77.6%, so United on IAH to DTW runs 7 points behind the country as a whole. Across a thousand flights that is about 73 extra late arrivals.

On time

70.3%

Arrivals under 15 minutes late, of 279 completed flights

Avg delay

58 min

Across delayed arrivals only, not all flights

Cancelled

1.41%

National rate is 1.81%

Whole route

78.8%

Every carrier on IAH to DTW, 2,137 flights

These figures cover 283 flights between July 2025 and June 2026. Beyond the headline rate, 10.4% of arrivals land a full hour or more behind schedule. That is the number that wrecks a connection, and it is not visible in an on-time percentage alone.

Carrier by carrier

United against every carrier on IAH to DTW

United flew 283 of the 2,137 flights on IAH to DTW, about 13% of it. Its 70.3% on time is 9 points worse than the route as a whole, which runs 78.8%. Ranked by on-time rate it is number four of five carriers on the route, where the range runs from SkyWest at 100.0% to Frontier at 68.6%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The two carriers here are closely matched: 6 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.

On-time performance by carrier on IAH to DTW
Airline	Flights	On time	Avg delay	Cancelled	Grade
SkyWest Airlinesthin sample	3	100.0%	—	0.00%	A+
Delta Air Lines	1,322	82.3%	76 min	0.76%	B+
Spirit Airlines	408	76.4%	88 min	2.45%	B
United Airlines (this page)thin sample	283	70.3%	58 min	1.41%	C
Frontier Airlinesthin sample	121	68.6%	54 min	1.65%	C

No carrier stands out. Delta tops the table at 82.3%, 6 points clear of the bottom, which is inside the range this kind of sample moves year to year.

Departure window

When United runs best on this route

Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 283 flights.

5am–8am—
8am–11am—
11am–2pm1 flights—
2pm–5pm—
5pm–8pm46 flights69.6%
8pm–5am236 flights70.3%

Scale runs 60% to 75%. Rows with fewer than 30 flights show a dash.

The overnight block holds up unusually well at 70.3% on time across 236 flights. Red-eyes fly into empty airspace and empty gates, and they are the first rotation of the aircraft's day rather than the last. The 8pm–5am window is the busiest, with 236 flights scheduled in it.

Across the year

United on IAH to DTW through the year

Jul–Sep 202586 flights69.9%
Oct–Dec 202553 flights71.7%
Jan–Mar 202653 flights67.3%
Apr–Jun 202691 flights71.4%

Scale runs 60% to 75%. Rows with fewer than 30 flights show a dash.

Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 70.3% on time across 283 flights.

Quarter by quarter United on IAH to DTW held fairly steady: 69.9% in Jul–Sep 2025, 71.7% in Oct–Dec 2025, 67.3% in Jan–Mar 2026 and 71.4% in Apr–Jun 2026. A spread of 4 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Across the week, Wednesday is the strongest day at 85.0% on time and Sunday the weakest at 60.0%. 25 points is a smaller lever than departure hour, but it is free.

Delay causes

Why United runs late on this route

One category carries most of the weight here. Carrier accounts for 50% of the 4,779 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.

Carrier
50%
Late-arriving aircraft
38%
National Airspace System
11%
Extreme weather
1%

38% 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 4,779 reported delay minutes here, that single category outweighs weather by 32 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. The split is drawn from 4,779 reported delay minutes.

The largest share of delay minutes, 50%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 2,373 of the 4,779 delay minutes reported here.

Cancellations sit at 1.41% against a national 1.81%, which is ordinary. Diversions add another 0.00%.

Connections and stage length

What a delay here costs

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 10.4% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.

The 1,075 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.

The return leg is a different operation and performs like one: it runs 87.0% on time across 281 flights, 17 points above this direction. Departure banks, aircraft rotations and the congestion at each end all differ, so scoring the two directions together would average away a real 17 points of difference.

One caution: this is a thin sample. 283 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.

What to do with this

Booking United on IAH to DTW

Put together: treat all of this as provisional. 283 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 70.3% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 279 completed flights over 12 months sit behind that.

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures