Flight number record

UA 1542

United Airlines · Houston to San Antonio

Route: IAH → SAT
Departs: 20:05
Flights: 340
Period: September 2025 to August 2026

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

UA 1542 lands a B+, about a point better than the national rate of 77.3%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 340 flights, with a median arrival 7 minutes early.

On time

78.2%

Arrivals under 15 minutes late, of 339 completed flights

Avg delay

56 min

Across delayed arrivals only, not all flights

Cancelled

0.29%

National rate is 1.89%

1 hour+ late

7.4%

National rate is 8.3%

These figures cover 340 flights between September 2025 and August 2026. The median arrival is 7 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.

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Schedule

When UA 1542 flies

UA 1542 flies IAH to SAT without a single fixed slot. Its most common scheduled departure was 20:05, used on 82 of 340 flights, with 20:10 (60 flights) and 20:09 (36 flights) next.

Departs 20:0582 flights24.1%
Departs 20:1060 flights17.6%
Departs 20:0936 flights10.6%

Scale runs 0% to 100%.

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

A 20:05 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.1%, and UA 1542 runs 8 points better at 78.2%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.

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Against the route

UA 1542 next to IAH to SAT

Every carrier on IAH to SAT combined arrived on time 83.1% of the time across 2,373 flights, so UA 1542 is 5 points behind it. United flew 2,247 flights on the same city pair under all its flight numbers, including this one, and those ran 83.0% on time. Across its whole network United Airlines managed 78.8%, close to this flight's figure.

UA 1542 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
UA 1542thin sample	340	78.2%	56 min	0.29%	B+
All United Airlines on IAH–SAT	2,247	83.0%	58 min	0.36%	B+
All carriers on IAH–SAT	2,373	83.1%	58 min	0.38%	B+
United Airlines, whole network	830,825	78.8%	73 min	1.02%	B

Across the year

UA 1542 quarter by quarter

UA 1542 did not run the same all year. Its best quarter was Jul–Sep 2025 at 93.3% on time and its weakest Apr–Jun 2026 at 69.2%, a swing of 24 points on roughly 68 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 202530 flights93.3%
Oct–Dec 202591 flights78.0%
Jan–Mar 202666 flights86.2%
Apr–Jun 202691 flights69.2%
Jul–Sep 202662 flights75.8%

Scale runs 60% to 100%.

By weekday, UA 1542 ranged from 72.3% on Thursday to 81.6% on Tuesday. With about 49 flights behind each day, a spread of 9 points is inside normal variation, so the day you fly is not worth changing for this flight.

Arrival by arrival

How late UA 1542 runs when it is late

The 74 late arrivals split 26 under half an hour, 23 between 30 and 60 minutes, and 25 an hour or more.

15+ min early81 flights23.9%
Within 15 min184 flights54.3%
15–29 min late26 flights7.7%
30–59 min late23 flights6.8%
1–2 hours late20 flights5.9%
2+ hours late5 flights1.5%

Scale runs 0% to 100%.

Share of 339 completed flights by arrival against schedule.

15 of 78 late departures made up the time and arrived on time, 19% of them. 11 flights left on time and still arrived late.

The worst days

Worst days for UA 1542

The latest arrival of the period was on 11 June 2026, 5 hours 37 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on four of the five worst days.

The latest arrivals of UA 1542 in the period
Date	Arrived late by	Largest filed cause
11 June 2026	5 hours 37 minutes	Late-arriving aircraft
27 July 2026	4 hours 12 minutes	Late-arriving aircraft
4 April 2026	2 hours 54 minutes	Late-arriving aircraft
21 May 2026	2 hours 17 minutes	National Airspace System
8 August 2026	2 hours 10 minutes	Late-arriving aircraft

Delay causes

Why UA 1542 runs late

Late-arriving aircraft accounts for 49% of the 4,168 delay minutes carriers reported here, and the remaining four split what is left.

Late-arriving aircraft
49%
Carrier
39%
National Airspace System
9%
Extreme weather
3%

49% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 4,168 reported delay minutes here, that single category outweighs weather by 18 to one. The split is drawn from 4,168 delay minutes reported on UA 1542.

Cancellations are rare at 0.29%, below the national 1.89% 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

7.4% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about an hour, 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 (1), 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, read UA 1542 as 78.2% on time with 0.29% cancelled over 340 flights. Those are rates from the past twelve months, not a forecast for any particular day.

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, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures