Carrier performance at one airport
DL→SAT
Delta Air Lines at San Antonio International
- Departures
- 6,845
- Period
- July 2025 to June 2026
- Routes
- 7
- Rank here
- #1 of 9
Delta Air Lines at San Antonio earns a A. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 8 points better than the national rate of 77.6%. When something does go wrong the average delay runs a little over an hour. That rests on 6,845 flights, of which Delta Air Lines flew 6,845 at 86.0% on time.
Measured against the airport rather than the country, Delta Air Lines runs 4 points ahead of the 81.8% weighted average across all carriers at SAT. That is the comparison worth making: every operator here works the same runways, the same airspace and the same weather.
Key figures
On time
86.0%
6,722 completed departures
Avg delay
79 min
Across delayed flights only
Cancelled
1.42%
At SAT, this carrier only
Rank here
#1
Of 9 carriers clearing the floor at SAT
These figures cover 6,845 flights between July 2025 and June 2026. The median arrival is 10 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.
Against the competition
Every carrier at SAT, ranked
The choice of carrier is not cosmetic here. Delta Air Lines arrives on time 86.0% of the time; Envoy Air manages 73.7%. Sample sizes sit next to every figure, because a two-point gap across 961 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines (this page) | 6,845 | 86.0% | 79 min | 1.42% | A |
| SkyWest Airlines | 1,624 | 84.8% | 111 min | 1.42% | B |
| United Airlines | 5,667 | 83.4% | 73 min | 0.72% | B+ |
| American Airlines | 7,481 | 80.6% | 110 min | 2.58% | B |
| Southwest Airlines | 15,321 | 80.6% | 53 min | 0.55% | B+ |
| Spirit Airlines | 988 | 80.1% | 85 min | 3.14% | B− |
| Frontier Airlines | 903 | 77.4% | 87 min | 0.78% | B+ |
| Alaska Airlines | 558 | 77.0% | 56 min | 1.43% | B |
| Envoy Air | 961 | 73.7% | 71 min | 2.81% | C |
Spirit Airlines cancels 3.1% 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.
Route by route
Where Delta Air Lines flies from SAT
Delta Air Lines operates 7 routes out of SAT with enough volume to report. Route records inside one carrier at one airport still spread widely, because a short shuttle and a transcontinental have very different exposure to a late inbound.
| Route | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SAT to ATL · Atlanta | 2,609 | 87.8% | 75 min | 1.76% | A |
| SAT to SLC · Salt Lake City | 1,008 | 86.6% | 70 min | 0.89% | A+ |
| SAT to DTW · Detroit | 934 | 90.2% | 72 min | 0.75% | A+ |
| SAT to MSP · Minneapolis | 892 | 85.2% | 72 min | 1.35% | A |
| SAT to LAX · Los Angeles | 684 | 89.4% | 107 min | 0.44% | A+ |
| SAT to JFK · New Yorkthin sample | 362 | 80.4% | 110 min | 3.31% | B− |
| SAT to BOS · Bostonthin sample | 355 | 60.9% | 80 min | 2.25% | D |
Departure window
Best time of day for this operation
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 16 points, against 12 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am2,166 flights93.9%
- 8am–11am545 flights92.5%
- 11am–2pm1,697 flights81.6%
- 2pm–5pm1,517 flights78.2%
- 5pm–8pm920 flights84.5%
- 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 93.9% of the time, against 78.2% for the afternoon window. That is 16 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 2,166 flights scheduled in it.
Across the year
Seasonal pattern
July is the worst month at 79.7% on time, 10 points below November, the best at 89.3%. 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. May was the busiest month here, with 611 flights.
Delay causes
What holds this operation up
- 39%Carrier
- 37%Late-arriving aircraft
- 19%National Airspace System
- 4%Extreme weather
- 0%Security
37% 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 75,000 reported delay minutes here, that single category outweighs weather by 8 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 74,536 reported delay minutes.
Cancellations sit at 1.42% against a national 1.81%, which is ordinary. Diversions add another 0.38%.
5.2% 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 are the a little over an hour kind, which a normal layover absorbs.
The sample behind these figures is 6,845 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.
Put together: take the 5am–8am departure, avoid July if the dates are flexible, and if two carriers are within a few dollars of each other, Delta is the one with the record behind it. None of that guarantees an on-time arrival; it moves the odds by 16 points, which is the most any booking decision can do. 6,722 completed flights over 12 months sit behind that.
Common questions
Delta Air Lines at SAT
How often is Delta Air Lines at SAT delayed?
About one flight in seven arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 14.0% of the 6,845 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 Delta Air Lines at SAT?
Delta Air Lines leads at 86.0% on time across 6,845 flights. Envoy Air is at the other end on 73.7%, a gap of 12 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 Delta Air Lines at SAT?
The 5am–8am departure window is the strongest at 93.9% on time. The 2pm–5pm window is the weakest at 78.2%, 16 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 July delays on Delta Air Lines at SAT?
July is the weakest month at 79.7% on time, compared with 89.3% in November. Across the year that is 10 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
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.