Flight number record

AA 1543

American Airlines · Chicago to San Diego

Route: ORD → SAN
Departs: 17:49
Flights: 272
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s AA 1543, check with American Airlines.

AA 1543 draws a D. About one flight in three arrives at least 15 minutes late, and the typical late arrival is an hour and a half behind schedule. Build slack into anything you connect to. That rests on 272 flights, with a median arrival 3 minutes late.

The national on-time rate over the same period is 77.6%, so AA 1543 runs 13 points behind the country as a whole. Across a thousand flights that is about 133 extra late arrivals.

On time

64.3%

Arrivals under 15 minutes late, of 263 completed flights

Avg delay

85 min

Across delayed arrivals only, not all flights

Cancelled

2.94%

National rate is 1.81%

1 hour+ late

14.1%

National rate is 8.1%

These figures cover 272 flights between July 2025 and June 2026. Beyond the headline rate, 14.1% 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.

Schedule

When AA 1543 flies

AA 1543 flies ORD to SAN without a single fixed slot. Its most common scheduled departure was 17:49, used on 46 of 272 flights, with 18:10 (43 flights) and 19:50 (36 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 17:4946 flights16.9%
Departs 18:1043 flights15.8%
Departs 19:5036 flights13.2%

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 17:49 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.2%, and AA 1543 runs 4 points worse at 64.3%. 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

AA 1543 next to ORD to SAN

Every carrier on ORD to SAN combined arrived on time 71.2% of the time across 3,807 flights, so AA 1543 is 7 points behind it. American flew 1,385 flights on the same city pair under all its flight numbers, including this one, and those ran 66.3% on time. Across its whole network American Airlines managed 74.4%, which this flight trails by 10 points.

AA 1543 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
AA 1543thin sample	272	64.3%	85 min	2.94%	D
All American Airlines on ORD–SAN	1,385	66.3%	65 min	1.73%	C
All carriers on ORD–SAN	3,807	71.2%	67 min	1.18%	C
American Airlines, whole network	986,297	74.4%	85 min	2.29%	C

Across the year

AA 1543 quarter by quarter

AA 1543 did not run the same all year. Its best quarter was Oct–Dec 2025 at 70.2% on time and its weakest Jul–Sep 2025 at 60.0%, a swing of 10 points on roughly 91 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 flights60.0%
Oct–Dec 202586 flights70.2%
Jan–Mar 202688 flights62.7%
Apr–Jun 20266 flights—

Scale runs 50% to 75%. Rows with fewer than 30 flights show a dash.

By weekday, AA 1543 ranged from 57.9% on Thursday to 69.2% on Tuesday. With about 39 flights behind each day, a spread of 11 points is inside normal variation, so the day you fly is not worth changing for this flight.

Delay causes

Why AA 1543 runs late

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 7,974 reported delay minutes.

Carrier
37%
Late-arriving aircraft
36%
National Airspace System
15%
Extreme weather
12%

Extreme weather accounts for 12% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the quarterly figures above are the more useful view of the risk. The national share is 6%, so this operation carries roughly 1.9 times the usual weather exposure. The split is drawn from 7,974 delay minutes reported on AA 1543.

Cancellations run at 2.94%, against 1.81% nationally. That is roughly one flight in 30 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.

Connections and routes

What a delay on this flight costs

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 14.1% 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 same number turns up on three other city pairs in the data, including LAS to PHL (43), SAN to ORD (41) and CVG to CLT (3), but none flew often enough under AA 1543 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to ORD to SAN only.

One caution: this is a thin sample. 272 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 AA 1543

For a booking, the cancellation rate is the figure to plan around on AA 1543: 2.94% of its 272 scheduled flights did not operate. A late arrival costs an hour and a half, but a cancellation costs the day, so leave a later option open.

Where to go next

A flight number here means American 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