Carrier route record

MQIAH→MIA

Envoy Air · Houston to Miami

Flights: 122
Period: July 2025 to June 2026
Share of route: 3%
Carriers: 6

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

Envoy on IAH to MIA lands a B+, about a point better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by roughly 50 minutes on average. That is a workable record, not a spotless one. That rests on 122 flights. The strongest carrier on the route with a full sample, United Airlines, flew 1,479 at 80.3% on time.

United Airlines is the most reliable of the three carriers covered here at 80.3% on time across 1,479 flights.

On time

78.5%

Arrivals under 15 minutes late, of 121 completed flights

Avg delay

52 min

Across delayed arrivals only, not all flights

Cancelled

0.00%

National rate is 1.81%

Whole route

77.8%

Every carrier on IAH to MIA, 3,736 flights

These figures cover 122 flights between July 2025 and June 2026. The median arrival is 12 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

Envoy against every carrier on IAH to MIA

Envoy flew 122 of the 3,736 flights on IAH to MIA, about 3% of it. Its 78.5% on time is about level with the route as a whole at 77.8%. Ranked by on-time rate it is number two of six carriers on the route, where the range runs from United at 80.3% to Republic at 64.3%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The choice of carrier is not cosmetic here. United Airlines arrives on time 80.3% of the time; Spirit Airlines manages 70.7%. Sample sizes sit next to every figure, because a two-point gap across 441 flights means less than a ten-point one.

On-time performance by carrier on IAH to MIA
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlines	1,479	80.3%	61 min	0.41%	B+
Envoy Air (this page)thin sample	122	78.5%	52 min	0.00%	B+
American Airlines	1,526	78.3%	111 min	1.31%	B
Spirit Airlines	441	70.7%	79 min	3.17%	C−
Frontier Airlinesthin sample	154	68.9%	142 min	1.95%	C
Republic Airwaysthin sample	14	64.3%	173 min	0.00%	D+

Spirit Airlines cancels 3.2% 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.

Departure window

When Envoy 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 122 flights.

5am–8am—
8am–11am—
11am–2pm36 flights74.3%
2pm–5pm63 flights81.0%
5pm–8pm23 flights—
8pm–5am—

Scale runs 65% to 85%. Rows with fewer than 30 flights show a dash.

The weak window here is the middle of the day, not the evening: 11am–2pm runs 74.3% on time against 81.0% for 2pm–5pm. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 2pm–5pm window is the busiest, with 63 flights scheduled in it.

Across the year

Envoy on IAH to MIA through the year

Jul–Sep 202529 flights—
Oct–Dec 202559 flights84.7%
Jan–Mar 202616 flights—
Apr–Jun 202618 flights—

Scale runs 75% to 90%. 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 78.5% on time across 122 flights.

Split by quarter, Envoy on IAH to MIA logged 29 flights in Jul–Sep 2025, 59 flights in Oct–Dec 2025, 16 flights in Jan–Mar 2026 and 18 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 78.5% annual figure is the one to use.

Delay causes

Why Envoy runs late on this route

One category carries most of the weight here. National Airspace System accounts for 42% of the 1,360 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.

National Airspace System
42%
Late-arriving aircraft
35%
Carrier
20%
Extreme weather
2%

35% 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 1,360 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 1,360 reported delay minutes.

42% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 575 minutes out of 1,360, against a national NAS share of 21%.

Cancellations are rare at 0.00%, below the national 1.81% and low enough to earn the plus on the grade. Almost no flights are called off; the risk here is arriving late, not not arriving.

Connections and stage length

What a delay here costs

5.8% 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 roughly 50 minutes, which a normal layover absorbs.

The 964 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 86.9% on time across 122 flights, 8 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 8 points of difference.

One caution: this is a thin sample. 122 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 Envoy on IAH to MIA

Put together: treat all of this as provisional. 122 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 78.5% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 121 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