Carrier route record
AASEA→PHL
American Airlines · Seattle to Philadelphia
- Flights
- 660
- 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 SEA to PHL earns a B. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 7 points better than the national rate of 77.3%. When something does go wrong the average delay runs close to two hours. That rests on 660 flights, with a median arrival 13 minutes early.
Set against the rest of the country, American's SEA to PHL record is 7 points better than the US average of 77.3%. That gap is worth roughly 73 fewer late arrivals for every thousand flights.
Key figures
On time
84.6%
Arrivals under 15 minutes late, of 642 completed flights
Avg delay
104 min
Across delayed arrivals only, not all flights
Cancelled
2.12%
National rate is 1.89%
Whole route
82.7%
Every carrier on SEA to PHL, 1,431 flights
These figures cover 660 flights between September 2025 and August 2026. The median arrival is 13 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.
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Carrier by carrier
American against every carrier on SEA to PHL
American flew 660 of the 1,431 flights on SEA to PHL, about 46% of it. Its 84.6% on time is 2 points better than the route as a whole, which runs 82.7%. Ranked by on-time rate it is first of three carriers on the route, where the range runs from American at 84.6% to Alaska at 80.7%. 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) | 660 | 84.6% | 104 min | 2.12% | B |
| Delta Air Linesthin sample | 114 | 83.2% | 54 min | 0.88% | B+ |
| Alaska Airlines | 657 | 80.7% | 46 min | 1.07% | B |
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Departure window
When American runs best on this route
Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 660 flights.
- 5am–8am69 flights86.4%
- 8am–11am103 flights81.6%
- 11am–2pm162 flights82.6%
- 2pm–5pm—
- 5pm–8pm—
- 8pm–5am326 flights86.1%
Scale runs 75% to 90%. Rows with fewer than 30 flights show a dash.
The overnight block holds up unusually well at 86.1% on time across 326 flights. Red-eyes fly into empty airspace and empty gates, and they are the first rotation of the aircraft's day rather than the last. The 8pm–5am window is the busiest, with 326 flights scheduled in it.
Across the year
American on SEA to PHL through the year
July is the worst month at 74.1% on time, 19 points below October, the best at 93.4%. 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. July was the busiest month here, with 91 flights.
Across the week, Tuesday is the strongest day at 88.2% on time and Thursday the weakest at 80.0%, a spread of 8 points.
Arrival by arrival
How late American on SEA to PHL runs when it is late
American on SEA to PHL often beats the schedule: 305 of 642 completed flights, 48%, arrived 15 minutes or more early. The 99 late arrivals split 44 under half an hour, 15 between 30 and 60 minutes, and 40 an hour or more.
- 15+ min early305 flights47.5%
- Within 15 min238 flights37.1%
- 15–29 min late44 flights6.9%
- 30–59 min late15 flights2.3%
- 1–2 hours late17 flights2.6%
- 2+ hours late23 flights3.6%
Scale runs 0% to 100%.
Share of 642 completed flights by arrival against schedule.
A late pushback is often recovered here: of 144 departures that left 15 minutes late or more, 61 still arrived on time. 16 flights left on time and still arrived late.
The worst days
Worst days for American on SEA to PHL
The latest arrival of the period was on 1 August 2026, 23 hours 26 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The five worst days are spread across August, January, June, September and October, with no single month standing out.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 1 August 2026 | 23 hours 26 minutes | Carrier |
| 25 January 2026 | 16 hours 48 minutes | Extreme weather |
| 19 June 2026 | 11 hours 7 minutes | Late-arriving aircraft |
| 28 September 2025 | 9 hours 3 minutes | Late-arriving aircraft |
| 5 October 2025 | 6 hours | 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 10,000 reported delay minutes.
- 42%Late-arriving aircraft
- 40%Carrier
- 11%Extreme weather
- 7%National Airspace System
Extreme weather accounts for 11% 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 monthly strip above is the more useful view of the risk. The national share is 6%, so this operation carries roughly 1.8 times the usual weather exposure. The split is drawn from 10,313 reported delay minutes.
42% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 10,000 reported delay minutes here, that single category outweighs weather by 4 to one.
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
6.2% 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 close to two hours, 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 70.8% on time across 661 flights, 14 points below 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. 660 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 SEA to PHL
Put together: treat all of this as provisional. 660 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 84.6% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 642 completed flights over 12 months sit behind that.
Related
Where to go next
- SEA to PHL, every carrier
- American on PHL to SEA, the return leg
- Delta Air Lines on SEA to PHL83.2%
- Alaska Airlines on SEA to PHL80.7%
- American Airlines network-wide record
- Seattle-Tacoma International (SEA) delay statistics
- Philadelphia International (PHL) delay statistics
- Why the first flight of the morning is statistically safest
- 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.