Route reliability record
ORD→SAT
Chicago to San Antonio
- Flights
- 1,966
- Period
- July 2025 to June 2026
- Distance
- 1,041 mi
- Carriers
- 5
This route sits in the middle of the pack with a C. Close to three flights in four arrive on time by the DOT's definition, 3 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 1,966 ORD to SAT flights, of which United Airlines flew 833 at 75.6% on time.
Best time to fly ORD to SAT: a 8am–11am departure, ideally on a Tuesday. Flights in that window arrived on time 83.9% of the time and Tuesday flights 80.4%, against 74.5% for the route overall.
The US average over the same twelve months is 77.6%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
74.5%
Arrivals under 15 minutes late, of 1,921 completed flights
Avg delay
70 min
Across delayed arrivals only, not all flights
Cancelled
2.03%
National rate is 1.81%
Best carrier
United
75.6% on time across 833 flights
These figures cover 1,966 flights between July 2025 and June 2026. Beyond the headline rate, 10.3% 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
Which airline is most reliable on ORD to SAT
The choice of carrier is not cosmetic here. United Airlines arrives on time 75.6% of the time; American Airlines manages 68.7%. Sample sizes sit next to every figure, because a two-point gap across 548 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Republic Airwaysthin sample | 101 | 82.3% | 62 min | 3.96% | B− |
| SkyWest Airlinesthin sample | 132 | 80.5% | 64 min | 3.03% | B− |
| Envoy Airthin sample | 352 | 76.8% | 57 min | 2.56% | B |
| United Airlines | 833 | 75.6% | 74 min | 1.08% | B |
| American Airlines | 548 | 68.7% | 74 min | 2.55% | C |
United leads American by 7 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Flight by flight
Flights on ORD to SAT
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
Best ways to make this trip
The most reliable ways to fly Chicago to San Antonio
Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. ORD → SATChicago to San Antonio | United Airlines | 74.8% | 75.6% | 1.08% | 8am–11am, Tue | UA 490 08:45 |
| 2. ORD → SATChicago to San Antonio | American Airlines | 66.9% | 68.7% | 2.55% | 8am–11am, Tue | — |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 20 points, against 7 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am—
- 8am–11am678 flights83.9%
- 11am–2pm343 flights77.1%
- 2pm–5pm265 flights71.9%
- 5pm–8pm210 flights64.2%
- 8pm–5am470 flights65.1%
Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 64.2% on time, against 83.9% for the 8am–11am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 8am–11am window is the busiest, with 678 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 17 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
June is the worst month at 67.1% on time, 17 points below October, the best at 83.8%. 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. March was the busiest month here, with 179 flights.
Across the week, Tuesday is the strongest day at 80.4% on time and Sunday the weakest at 70.6%. 10 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Late-arriving aircraft accounts for 49% of the 34,000 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.
- 49%Late-arriving aircraft
- 27%Carrier
- 17%National Airspace System
- 7%Extreme weather
- 0%Security
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 34,000 reported delay minutes here, that single category outweighs weather by 7 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 34,386 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 83.9% on time here.
Cancellations sit at 2.03% against a national 1.81%, which is ordinary. Diversions add another 0.25%.
Connections and stage length
What a delay here actually costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 10.3% 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 1,041 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 runs 76.3% on time across 1,968 flights, within 2 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 1,966 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.
Work out the risk of missing a connection in SAT after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. October runs 83.8% on time and June 67.1%, a swing of 17 points. If the dates move at all, move them out of June before you think about anything else. 1,921 completed flights over 12 months sit behind that.
Common questions
ORD to SAT questions
How often is ORD to SAT delayed?
About one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 25.5% of the 1,966 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on ORD to SAT?
United Airlines leads at 75.6% on time across 833 flights. American Airlines is at the other end on 68.7%, a gap of 7 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on ORD to SAT?
The 8am–11am departure window is the strongest at 83.9% on time. The 5pm–8pm window is the weakest at 64.2%, 20 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are June delays on ORD to SAT?
June is the weakest month at 67.1% on time, compared with 83.8% in October. Across the year that is 17 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- SAT to ORD — the return legseparate record
- Chicago O'Hare International (ORD) delay statistics
- San Antonio International (SAT) delay statistics
- Republic Airways on ORD to SAT82.3%
- SkyWest Airlines on ORD to SAT80.5%
- Envoy Air on ORD to SAT76.8%
- United Airlines on ORD to SAT75.6%
- American Airlines on ORD to SAT68.7%
- ORD to LGA, a related route67.3%
- DFW to SAT, a related route67.0%
- ORD to BOS, a related route67.6%
- Republic Airways on-time record82.3%
- SkyWest Airlines on-time record80.5%
- Envoy Air on-time record76.8%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. ORD to SAT and SAT to ORD are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.