Flight number record

AS 503

Alaska Airlines · Austin to Seattle

Route: AUS → SEA
Departs: 13:36
Flights: 335
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s AS 503, check with Alaska Airlines.

AS 503 earns an 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 335 flights, with a median arrival 8 minutes early.

Set against the rest of the country, AS 503's record is 8 points better than the US average of 77.6%. That gap is worth roughly 82 fewer late arrivals for every thousand flights.

On time

85.8%

Arrivals under 15 minutes late, of 330 completed flights

Avg delay

68 min

Across delayed arrivals only, not all flights

Cancelled

1.19%

National rate is 1.81%

1 hour+ late

5.5%

National rate is 8.1%

These figures cover 335 flights between July 2025 and June 2026. The median arrival is 8 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.

Schedule

When AS 503 flies

AS 503 flies AUS to SEA without a single fixed slot. Its most common scheduled departure was 13:36, used on 76 of 335 flights, with 13:33 (46 flights) and 13:40 (45 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 13:3676 flights22.7%
Departs 13:3346 flights13.7%
Departs 13:4045 flights13.4%

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 13:36 departure sits in the 11am–2pm window. Across every US flight scheduled in that window the on-time rate is 78.8%, and AS 503 runs 7 points better at 85.8%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.

Against the route

AS 503 next to AUS to SEA

Every carrier on AUS to SEA combined arrived on time 82.8% of the time across 2,058 flights, so AS 503 is 3 points ahead of it. Alaska flew 1,096 flights on the same city pair under all its flight numbers, including this one, and those ran 82.0% on time. Across its whole network Alaska Airlines managed 79.1%, which this flight beats by 7 points.

AS 503 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
AS 503thin sample	335	85.8%	68 min	1.19%	A
All Alaska Airlines on AUS–SEA	1,096	82.0%	55 min	1.00%	B
All carriers on AUS–SEA	2,058	82.8%	69 min	1.07%	B
Alaska Airlines, whole network	293,372	79.1%	52 min	1.28%	B

Across the year

AS 503 quarter by quarter

AS 503 did not run the same all year. Its best quarter was Apr–Jun 2026 at 93.5% on time and its weakest Oct–Dec 2025 at 81.5%, a swing of 12 points on roughly 84 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 flights84.6%
Oct–Dec 202592 flights81.5%
Jan–Mar 202688 flights85.9%
Apr–Jun 202663 flights93.5%

Scale runs 75% to 100%. Rows with fewer than 30 flights show a dash.

By weekday, AS 503 ranged from 83.0% on Sunday to 89.4% on Tuesday. With about 48 flights behind each day, a spread of 6 points is inside normal variation, so the day you fly is not worth changing for this flight.

Delay causes

Why AS 503 runs late

One category carries most of the weight here. Late-arriving aircraft accounts for 43% of the 3,212 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.

Late-arriving aircraft
43%
Carrier
30%
National Airspace System
15%
Extreme weather
7%
Security
5%

43% 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 3,212 reported delay minutes here, that single category outweighs weather by 6 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 3,212 delay minutes reported on AS 503.

Cancellations sit at 1.19% against a national 1.81%, which is ordinary. Diversions add another 0.30%.

Connections and routes

What a delay on this flight costs

5.5% 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 last a little over an hour, which a normal layover absorbs.

At 1,770 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.

Every one of the 335 flights under AS 503 in the data flew AUS to SEA. The number was not reused on any other city pair, which makes this a clean record of one route.

One caution: this is a thin sample. 335 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 AS 503

For a booking, AS 503 has one of the better records a US domestic flight can show: 85.8% on time and 1.19% cancelled. That is a base rate, not a promise about any single day.

Where to go next

A flight number here means Alaska 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