Carrier route record
AAPHL→SEA
American Airlines · Philadelphia to Seattle
- Flights
- 661
- Period
- September 2025 to August 2026
- Share of route
- 46%
- Carriers
- 3
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with American Airlines.
American on PHL to SEA sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 7 points worse than the national rate of 77.3%. The late ones land roughly 55 minutes behind schedule. That rests on 661 flights, with a median arrival 3 minutes early.
The national on-time rate over the same period is 77.3%, so American on PHL to SEA runs 7 points behind the country as a whole. Across a thousand flights that is about 65 extra late arrivals.
Key figures
On time
70.8%
Arrivals under 15 minutes late, of 643 completed flights
Avg delay
53 min
Across delayed arrivals only, not all flights
Cancelled
2.12%
National rate is 1.89%
Whole route
69.4%
Every carrier on PHL to SEA, 1,431 flights
These figures cover 661 flights between September 2025 and August 2026. Beyond the headline rate, 8.1% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
American against every carrier on PHL to SEA
American flew 661 of the 1,431 flights on PHL to SEA, about 46% of it. Its 70.8% on time is about level with the route as a whole at 69.4%. Ranked by on-time rate it is first of three carriers on the route, where the range runs from American at 70.8% to Alaska at 68.0%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| American Airlines (this page) | 661 | 70.8% | 53 min | 2.12% | C |
| Delta Air Linesthin sample | 113 | 69.4% | 76 min | 0.88% | C+ |
| Alaska Airlines | 657 | 68.0% | 51 min | 1.67% | C |
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
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 17 points, against half a point between the best and worst carrier.
- 5am–8am—
- 8am–11am208 flights82.1%
- 11am–2pm—
- 2pm–5pm4 flights—
- 5pm–8pm449 flights65.5%
- 8pm–5am—
Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.
Book the morning departure. Flights leaving between 8am–11am arrive on time 82.1% of the time, against 65.5% for the evening window. That is 17 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5pm–8pm window is the busiest, with 449 flights scheduled in it.
Across the year
American on PHL to SEA through the year
December is the weak month at 40.0% on time, against 88.9% in April. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. July was the busiest month here, with 91 flights.
Across the week, Tuesday is the strongest day at 77.5% on time and Friday the weakest at 67.0%, a spread of 11 points.
Arrival by arrival
How late American on PHL to SEA runs when it is late
American on PHL to SEA often beats the schedule: 195 of 643 completed flights, 30%, arrived 15 minutes or more early. The 188 late arrivals split 78 under half an hour, 58 between 30 and 60 minutes, and 52 an hour or more.
- 15+ min early195 flights30.3%
- Within 15 min260 flights40.4%
- 15–29 min late78 flights12.1%
- 30–59 min late58 flights9.0%
- 1–2 hours late33 flights5.1%
- 2+ hours late19 flights3.0%
Scale runs 0% to 100%.
Share of 643 completed flights by arrival against schedule.
A late pushback is often recovered here: of 160 departures that left 15 minutes late or more, 49 still arrived on time. In the other direction, 77 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at SEA.
The worst days
Worst days for American on PHL to SEA
The latest arrival of the period was on 18 June 2026, 5 hours 4 minutes behind schedule; most of its delay minutes were filed as national airspace system delay. On three of the five worst days the largest share was filed as carrier-caused (crew, maintenance, fuelling, baggage).
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 18 June 2026 | 5 hours 4 minutes | National Airspace System |
| 19 June 2026 | 3 hours 58 minutes | Carrier |
| 20 September 2025 | 3 hours 33 minutes | Carrier |
| 19 July 2026 | 3 hours 16 minutes | Late-arriving aircraft |
| 7 July 2026 | 3 hours 12 minutes | Carrier |
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 9,961 reported delay minutes.
- 38%National Airspace System
- 32%Carrier
- 24%Late-arriving aircraft
- 4%Extreme weather
- 1%Security
38% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 3,820 minutes out of 9,961, against a national NAS share of 21%. The split is drawn from 9,961 reported delay minutes.
Cancellations sit at 2.12% against a national 1.89%, which is ordinary. Diversions add another 0.61%.
Connections and stage length
What a delay here costs
8.1% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last roughly 55 minutes, which a normal layover absorbs.
At 2,379 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 84.6% on time across 660 flights, 14 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 14 points of difference.
One caution: this is a thin sample. 661 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 American on PHL to SEA
Put together: treat all of this as provisional. 661 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 70.8% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 643 completed flights over 12 months sit behind that.
Related
Where to go next
- PHL to SEA, every carrier
- American on SEA to PHL, the return leg
- Delta Air Lines on PHL to SEA69.4%
- Alaska Airlines on PHL to SEA68.0%
- American Airlines network-wide record
- Philadelphia International (PHL) delay statistics
- Seattle-Tacoma International (SEA) delay statistics
- The best time of day to fly, according to 7.05 million flight records
- Worst months to fly in the US, ranked by the data
Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.