Carrier route record

AAPHL→BOS

American Airlines · Philadelphia to Boston

Flights: 2,246
Period: July 2025 to June 2026
Share of route: 45%
Carriers: 4

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

American on PHL to BOS sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 6 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 2,246 flights. The strongest carrier on the route with a full sample, Republic Airways, flew 1,761 at 80.9% on time.

The national on-time rate over the same period is 77.6%, so American on PHL to BOS runs 6 points behind the country as a whole. Across a thousand flights that is about 62 extra late arrivals.

On time

71.4%

Arrivals under 15 minutes late, of 2,181 completed flights

Avg delay

82 min

Across delayed arrivals only, not all flights

Cancelled

2.89%

National rate is 1.81%

Whole route

75.2%

Every carrier on PHL to BOS, 4,956 flights

These figures cover 2,246 flights between July 2025 and June 2026. Beyond the headline rate, 13.8% 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 PHL to BOS

American flew 2,246 of the 4,956 flights on PHL to BOS, about 45% of it. Its 71.4% on time is 4 points worse than the route as a whole, which runs 75.2%. Ranked by on-time rate it is last of four carriers on the route, where the range runs from Frontier at 87.5% to American at 71.4%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The choice of carrier is not cosmetic here. Republic Airways arrives on time 80.9% of the time; JetBlue Airways manages 72.8%. Sample sizes sit next to every figure, because a two-point gap across 892 flights means less than a ten-point one.

On-time performance by carrier on PHL to BOS
Airline	Flights	On time	Avg delay	Cancelled	Grade
Frontier Airlinesthin sample	57	87.5%	43 min	1.75%	A
Republic Airways	1,761	80.9%	79 min	3.18%	B−
JetBlue Airways	892	72.8%	74 min	2.58%	C
American Airlines (this page)	2,246	71.4%	82 min	2.89%	C

Republic Airways cancels 3.2% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.

Flight by flight

American flight numbers on PHL to BOS

AA 187421:3069.5% · 295 flights

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 33 points, against 8 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am185 flights91.2%
8am–11am468 flights85.1%
11am–2pm345 flights78.5%
2pm–5pm404 flights57.8%
5pm–8pm516 flights58.5%
8pm–5am328 flights69.1%

Scale runs 50% to 95%. Rows with fewer than 30 flights show a dash.

Book the early departure. Flights leaving between 5am–8am arrive on time 91.2% of the time, against 57.8% for the afternoon window. That is 33 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 516 flights scheduled in it.

Across the year

American on PHL to BOS through the year

Darker means more delays. Figures are on-time percentages.January best, September worst

Delays peak in September, when the on-time rate falls to 58.3%. January is the strongest month at 81.9%. Moving a flexible trip across that boundary buys 24 points. June was the busiest month here, with 243 flights.

Across the week, Wednesday is the strongest day at 77.6% on time and Sunday the weakest at 64.0%. 14 points is a smaller lever than departure hour, but it is free.

Delay causes

Why American runs late on this route

One category carries most of the weight here. Late-arriving aircraft accounts for 49% of the 51,000 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
49%
Carrier
23%
National Airspace System
22%
Extreme weather
5%
Security
0%

49% 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 51,000 reported delay minutes here, that single category outweighs weather by 9 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 51,082 reported delay minutes.

The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 91.2% on time here.

Cancellations run at 2.89%, 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 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. 13.8% 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 280 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 5am–8am window matters as much as it does.

The return leg is a different operation and performs like one: it runs 75.9% on time across 2,249 flights, 5 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 5 points of difference.

The sample behind these figures is 2,246 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 PHL to BOS

Put together: the delay figures matter less here than the 2.89% cancellation rate. A late arrival costs you a little over an hour; a cancelled flight costs you the day. Book the 5am–8am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 2,181 completed flights over 12 months sit behind that.

Where to go next

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