Carrier route record

DLIAH→DTW

Delta Air Lines · Houston to Detroit

Flights: 1,322
Period: July 2025 to June 2026
Share of route: 62%
Carriers: 5

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

Delta on IAH to DTW lands a B+, 5 points better than the national rate of 77.6%. About one flight in six arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 1,322 flights, with a median arrival 8 minutes early.

Set against the rest of the country, Delta's IAH to DTW record is 5 points better than the US average of 77.6%. That gap is worth roughly 47 fewer late arrivals for every thousand flights.

On time

82.3%

Arrivals under 15 minutes late, of 1,306 completed flights

Avg delay

76 min

Across delayed arrivals only, not all flights

Cancelled

0.76%

National rate is 1.81%

Whole route

78.8%

Every carrier on IAH to DTW, 2,137 flights

These figures cover 1,322 flights between July 2025 and June 2026. The median arrival is 8 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.

Carrier by carrier

Delta against every carrier on IAH to DTW

Delta flew 1,322 of the 2,137 flights on IAH to DTW, most of the route. Its 82.3% on time is 4 points better than the route as a whole, which runs 78.8%. Ranked by on-time rate it is number two of five carriers on the route, where the range runs from SkyWest at 100.0% to Frontier at 68.6%. Three of those carriers flew fewer than 365 flights here, so treat their positions as rough.

Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.

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 (this page)	1,322	82.3%	76 min	0.76%	B+
Spirit Airlines	408	76.4%	88 min	2.45%	B
United Airlinesthin sample	283	70.3%	58 min	1.41%	C
Frontier Airlinesthin sample	121	68.6%	54 min	1.65%	C

Flight by flight

Delta flight numbers on IAH to DTW

Departure window

When Delta runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 21 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am365 flights90.0%
8am–11am—
11am–2pm365 flights81.5%
2pm–5pm345 flights84.2%
5pm–8pm247 flights69.4%
8pm–5am—

Scale runs 60% to 95%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 90.0% of the time, against 69.4% for the evening window. That is 21 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 365 flights scheduled in it.

Across the year

Delta on IAH to DTW through the year

Darker means more delays. Figures are on-time percentages.September best, March worst

September is the best month on the calendar at 90.7% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. March was the busiest month here, with 120 flights.

Across the week, Tuesday is the strongest day at 85.2% on time and Saturday the weakest at 80.3%. 5 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Delta runs late on this route

One category carries most of the weight here. Carrier accounts for 43% of the 17,000 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
43%
Late-arriving aircraft
40%
National Airspace System
14%
Extreme weather
2%

40% 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 17,000 reported delay minutes here, that single category outweighs weather by 17 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 17,441 reported delay minutes.

The largest share of delay minutes, 43%, 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 7,559 of the 17,000 delay minutes reported here.

Cancellations are rare at 0.76%, below the national 1.81% 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.

Connections and stage length

What a delay here costs

5.7% of arrivals land an hour or more late, close to the national 8.1%. 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 last a little over an hour, which a normal layover absorbs.

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 runs 79.8% on time across 1,322 flights, within 3 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

The sample behind these figures is 1,322 flights, enough that the headline rate is stable to within roughly a point. The hour-block and month splits divide that further, so read the thinner bars with more caution than the headline.

What to do with this

Booking Delta on IAH to DTW

Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 90.7% on time and March 74.1%, a swing of 17 points. If the dates move at all, move them out of March before you think about anything else. 1,306 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