Carrier route record

F9DTW→IAH

Frontier Airlines · Detroit to Houston

Flights: 120
Period: July 2025 to June 2026
Share of route: 6%
Carriers: 5

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

Frontier on DTW to IAH draws a C+. About one flight in three arrives at least 15 minutes late, and the typical late arrival is a little over an hour behind schedule. Build slack into anything you connect to. That rests on 120 flights. The strongest carrier on the route with a full sample, Delta Air Lines, flew 1,322 at 79.8% on time.

The national on-time rate over the same period is 77.6%, so Frontier on DTW to IAH runs 12 points behind the country as a whole. Across a thousand flights that is about 121 extra late arrivals.

On time

65.5%

Arrivals under 15 minutes late, of 119 completed flights

Avg delay

73 min

Across delayed arrivals only, not all flights

Cancelled

0.83%

National rate is 1.81%

Whole route

79.7%

Every carrier on DTW to IAH, 2,129 flights

These figures cover 120 flights between July 2025 and June 2026. Beyond the headline rate, 14.3% 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

Frontier against every carrier on DTW to IAH

Frontier flew 120 of the 2,129 flights on DTW to IAH, about 6% of it. Its 65.5% on time is 14 points worse than the route as a whole, which runs 79.7%. Ranked by on-time rate it is last of five carriers on the route, where the range runs from United at 87.0% to Frontier at 65.5%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The two carriers here are closely matched: about a point 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 DTW to IAH
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlinesthin sample	281	87.0%	53 min	1.42%	A
Delta Air Lines	1,322	79.8%	55 min	0.83%	B+
Spirit Airlines	403	78.5%	85 min	1.74%	B
SkyWest Airlinesthin sample	3	66.7%	19 min	0.00%	C+
Frontier Airlines (this page)thin sample	120	65.5%	73 min	0.83%	C+

No carrier stands out. Delta tops the table at 79.8%, about a point clear of the bottom, which is inside the range this kind of sample moves year to year.

Departure window

When Frontier 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 120 flights.

There are not enough flights in each departure window to split Frontier's DTW to IAH record by time of day without the percentages moving on noise. The headline rate of 65.5% is the reliable figure here.

Across the year

Frontier on DTW to IAH through the year

Oct–Dec 202517 flights—
Jan–Mar 202636 flights62.9%
Apr–Jun 202667 flights67.2%

Scale runs 55% 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 65.5% on time across 120 flights.

Split by quarter, Frontier on DTW to IAH logged 17 flights in Oct–Dec 2025, 36 flights in Jan–Mar 2026 and 67 flights in Apr–Jun 2026. Fewer than three of those quarters carried the 30 completed flights this site needs before printing a rate, so the 65.5% annual figure is the one to use.

Delay causes

Why Frontier runs late on this route

One category carries most of the weight here. Late-arriving aircraft accounts for 49% of the 2,980 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.

Late-arriving aircraft
49%
National Airspace System
25%
Carrier
23%
Extreme weather
2%

49% 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 2,980 reported delay minutes here, that single category outweighs weather by 25 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 2,980 reported delay minutes.

The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 69.6% on time here.

Cancellations are rare at 0.83%, 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

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 14.3% 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 68.6% on time across 121 flights, 3 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 3 points of difference.

One caution: this is a thin sample. 120 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 Frontier on DTW to IAH

Put together: treat all of this as provisional. 120 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 65.5% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 119 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