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DelayAtlas

Carrier route record

UAFLLIAH

United Airlines · Fort Lauderdale to Houston

Flights
1,792
Period
July 2025 to June 2026
Share of route
65%
Carriers
3
A+GRADE

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

United on FLL to IAH earns an A+. Close to nine flights in ten arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 11 points better than the national rate of 77.6%. When something does go wrong the average delay runs an hour and a half. That rests on 1,792 flights, with a median arrival 16 minutes early.

Set against the rest of the country, United's FLL to IAH record is 11 points better than the US average of 77.6%. That gap is worth roughly 107 fewer late arrivals for every thousand flights.

Key figures

On time

88.3%

Arrivals under 15 minutes late, of 1,774 completed flights

Avg delay

84 min

Across delayed arrivals only, not all flights

Cancelled

0.78%

National rate is 1.81%

Whole route

82.1%

Every carrier on FLL to IAH, 2,755 flights

These figures cover 1,792 flights between July 2025 and June 2026. The median arrival is 16 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

United against every carrier on FLL to IAH

United flew 1,792 of the 2,755 flights on FLL to IAH, most of the route. Its 88.3% on time is 6 points better than the route as a whole, which runs 82.1%. Ranked by on-time rate it is first of three carriers on the route, where the range runs from United at 88.3% to Frontier at 52.0%. One 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 FLL to IAH
AirlineFlightsOn timeAvg delayCancelledGrade
United Airlines (this page)1,79288.3%84 min0.78%A+
Spirit Airlines85972.5%75 min1.75%C
Frontier Airlinesthin sample10452.0%75 min1.92%F

Departure window

When United runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 18 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–8am347 flights97.1%
  • 8am–11am313 flights92.6%
  • 11am–2pm568 flights88.7%
  • 2pm–5pm81 flights83.8%
  • 5pm–8pm483 flights79.6%
  • 8pm–5am

Scale runs 70% to 100%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 97.1% of the time, against 79.6% for the evening window. That is 18 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 11am–2pm window is the busiest, with 568 flights scheduled in it.

Across the year

United on FLL to IAH through the year

On-time rate by calendar month91J94F86M87A86M86J80J83A94S95O88N87D
Darker means more delays. Figures are on-time percentages.October best, July worst

July is the worst month at 80.3% on time, 15 points below October, the best at 94.9%. 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. December was the busiest month here, with 184 flights.

Across the week, Thursday is the strongest day at 93.5% on time and Sunday the weakest at 80.8%. 13 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week88.7Mon91.4Tue90.3Wed93.5Thu88.3Fri85.7Sat80.8Sun
Monday: 88.7 percent on time. Tuesday: 91.4 percent on time. Wednesday: 90.3 percent on time. Thursday: 93.5 percent on time. Friday: 88.3 percent on time. Saturday: 85.7 percent on time. Sunday: 80.8 percent on time

Delay causes

Why United runs late on this route

One category carries most of the weight here. National Airspace System 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.

  • National Airspace System
    43%
  • Carrier
    28%
  • Late-arriving aircraft
    27%
  • Extreme weather
    3%

43% 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 7,425 minutes out of 17,000, against a national NAS share of 21%. The split is drawn from 17,422 reported delay minutes.

Cancellations are rare at 0.78%, 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

Badly late arrivals are rare here: only 4.6% land an hour or more behind schedule, against 8.1% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.

The 966 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 85.0% on time across 1,792 flights, 3 points below 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.

The sample behind these figures is 1,792 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 United on FLL to IAH

Put together: the calendar is the biggest lever here, not the carrier or the hour. October runs 94.9% on time and July 80.3%, a swing of 15 points. If the dates move at all, move them out of July before you think about anything else. 1,774 completed flights over 12 months sit behind that.

Related

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.