Carrier route record
AAORD→SAN
American Airlines · Chicago to San Diego
- Flights
- 1,385
- Period
- July 2025 to June 2026
- Share of route
- 36%
- Carriers
- 4
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with American Airlines.
American on ORD to SAN draws a C. About one flight in three arrives at least 15 minutes late, and the typical late arrival is about an hour behind schedule. Build slack into anything you connect to. That rests on 1,385 flights. The strongest carrier on the route with a full sample, United Airlines, flew 1,672 at 77.0% on time.
The national on-time rate over the same period is 77.6%, so American on ORD to SAN runs 11 points behind the country as a whole. Across a thousand flights that is about 113 extra late arrivals.
Key figures
On time
66.3%
Arrivals under 15 minutes late, of 1,357 completed flights
Avg delay
65 min
Across delayed arrivals only, not all flights
Cancelled
1.73%
National rate is 1.81%
Whole route
71.2%
Every carrier on ORD to SAN, 3,807 flights
These figures cover 1,385 flights between July 2025 and June 2026. Beyond the headline rate, 12.3% 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
American against every carrier on ORD to SAN
American flew 1,385 of the 3,807 flights on ORD to SAN, about 36% of it. Its 66.3% on time is 5 points worse than the route as a whole, which runs 71.2%. Ranked by on-time rate it is number three of four carriers on the route, where the range runs from United at 77.0% to Frontier at 53.2%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The choice of carrier is not cosmetic here. United Airlines arrives on time 77.0% of the time; Alaska Airlines manages 68.4%. Sample sizes sit next to every figure, because a two-point gap across 688 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 1,672 | 77.0% | 64 min | 0.30% | B+ |
| Alaska Airlines | 688 | 68.4% | 70 min | 2.33% | C |
| American Airlines (this page) | 1,385 | 66.3% | 65 min | 1.73% | C |
| Frontier Airlinesthin sample | 62 | 53.2% | 103 min | 0.00% | F+ |
United leads Alaska by 9 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Flight by flight
American flight numbers on ORD to SAN
Departure window
When American runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 31 points, against 9 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am155 flights81.0%
- 8am–11am369 flights71.4%
- 11am–2pm262 flights68.7%
- 2pm–5pm41 flights61.0%
- 5pm–8pm354 flights62.3%
- 8pm–5am204 flights50.3%
Scale runs 40% to 85%. Rows with fewer than 30 flights show a dash.
The 8pm–5am window is where this operation falls apart: 50.3% on time, against 81.0% for the 5am–8am 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 369 flights scheduled in it.
Across the year
American on ORD to SAN through the year
September is the best month on the calendar at 80.0% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. July was the busiest month here, with 151 flights.
Across the week, Tuesday is the strongest day at 69.7% on time and Sunday the weakest at 63.9%. 6 points is a smaller lever than departure hour, but it is free.
Delay causes
Why American runs late on this route
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 30,000 reported delay minutes.
- 39%Late-arriving aircraft
- 37%Carrier
- 18%National Airspace System
- 6%Extreme weather
39% 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 30,000 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 29,789 reported delay minutes.
The largest share of delay minutes, 37%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 11,000 of the 30,000 delay minutes reported here.
Cancellations sit at 1.73% against a national 1.81%, which is ordinary. Diversions add another 0.29%.
Connections and stage length
What a delay here costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 12.3% 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.
At 1,723 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg is a different operation and performs like one: it runs 77.3% on time across 1,386 flights, 11 points above 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 11 points of difference.
The sample behind these figures is 1,385 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 American on ORD to SAN
Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 80.0% on time and April 45.8%, a swing of 34 points. If the dates move at all, move them out of April before you think about anything else. 1,357 completed flights over 12 months sit behind that.
Related
Where to go next
- ORD to SAN, every carrier
- American on SAN to ORD, the return leg
- United Airlines on ORD to SAN77.0%
- Alaska Airlines on ORD to SAN68.4%
- American Airlines network-wide record
- Chicago O'Hare International (ORD) delay statistics
- San Diego International (SAN) delay statistics
- Why the first flight of the morning is statistically safest
- How often a connection fails at the major US hubs
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.