Flight number record

UA 1542

United Airlines · Houston to San Antonio

Route: IAH → SAT
Departs: 20:10
Flights: 340
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s UA 1542, check with United Airlines.

UA 1542 lands a B+, about a point worse than the national rate of 77.6%. About one flight in four arrives 15 minutes late or worse, and those flights are late by about 55 minutes on average. That is a workable record, not a spotless one. That rests on 340 flights, with a median arrival 5 minutes early.

On time

76.6%

Arrivals under 15 minutes late, of 337 completed flights

Avg delay

54 min

Across delayed arrivals only, not all flights

Cancelled

0.88%

National rate is 1.81%

1 hour+ late

6.8%

National rate is 8.1%

These figures cover 340 flights between July 2025 and June 2026. The median arrival is 5 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.

Schedule

When UA 1542 flies

UA 1542 flies IAH to SAT without a single fixed slot. Its most common scheduled departure was 20:10, used on 73 of 340 flights, with 20:20 (67 flights) and 20:09 (36 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 20:1073 flights21.5%
Departs 20:2067 flights19.7%
Departs 20:0936 flights10.6%

Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.

Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.

A 20:10 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.5%, and UA 1542 runs 6 points better at 76.6%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.

Against the route

UA 1542 next to IAH to SAT

Every carrier on IAH to SAT combined arrived on time 82.4% of the time across 2,411 flights, so UA 1542 is 6 points behind it. United flew 2,326 flights on the same city pair under all its flight numbers, including this one, and those ran 82.6% on time. Across its whole network United Airlines managed 79.0%, which this flight trails by 2 points.

UA 1542 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
UA 1542thin sample	340	76.6%	54 min	0.88%	B+
All United Airlines on IAH–SAT	2,326	82.6%	62 min	0.47%	B+
All carriers on IAH–SAT	2,411	82.4%	63 min	0.50%	B+
United Airlines, whole network	821,041	79.0%	72 min	1.01%	B

Across the year

UA 1542 quarter by quarter

UA 1542 did not run the same all year. Its best quarter was Jan–Mar 2026 at 86.2% on time and its weakest Apr–Jun 2026 at 69.2%, a swing of 17 points on roughly 85 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.

Jul–Sep 202592 flights75.6%
Oct–Dec 202591 flights78.0%
Jan–Mar 202666 flights86.2%
Apr–Jun 202691 flights69.2%

Scale runs 60% to 90%. Rows with fewer than 30 flights show a dash.

By weekday, UA 1542 did best on Tuesday at 82.0% on time and worst on Thursday at 68.1%. Each day rests on about 49 flights, so a gap of 14 points is worth noticing but could still narrow in another year.

Delay causes

Why UA 1542 runs late

One category carries most of the weight here. Late-arriving aircraft accounts for 49% of the 4,287 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%
Carrier
39%
National Airspace System
8%
Extreme weather
3%

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 4,287 reported delay minutes here, that single category outweighs weather by 16 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 4,287 delay minutes reported on UA 1542.

Cancellations are rare at 0.88%, 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 routes

What a delay on this flight costs

6.8% 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 about 55 minutes, which a normal layover absorbs.

The same number turns up on four other city pairs in the data, including PDX to IAH (36), ABQ to ORD (23) and LAS to LAX (14), but none flew often enough under UA 1542 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to IAH to SAT only.

One caution: this is a thin sample. 340 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 UA 1542

For a booking, UA 1542 is one of the weaker ways to fly IAH to SAT: 6 points below the route as a whole. If the schedule allows, compare it with the other departures listed on the route page before settling on this one.

Where to go next

A flight number here means United Airlines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.

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