Flight number record

AA 2539

American Airlines · Miami to Boston

Route: MIA → BOS
Departs: 19:50
Flights: 325
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s AA 2539, check with American Airlines.

AA 2539 draws a D. Roughly one flight in three arrives at least 15 minutes late, and the typical late arrival is a little over an hour behind schedule. Build slack into anything you connect to. That rests on 325 flights, with a median arrival 5 minutes late.

The national on-time rate over the same period is 77.6%, so AA 2539 runs 17 points behind the country as a whole. Across a thousand flights that is about 173 extra late arrivals.

On time

60.3%

Arrivals under 15 minutes late, of 317 completed flights

Avg delay

78 min

Across delayed arrivals only, not all flights

Cancelled

2.15%

National rate is 1.81%

1 hour+ late

17.0%

National rate is 8.1%

These figures cover 325 flights between July 2025 and June 2026. Beyond the headline rate, 17.0% 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 2539 flies

AA 2539 flies MIA to BOS without a single fixed slot. Its most common scheduled departure was 19:50, used on 66 of 325 flights, with 19:40 (44 flights) and 20:13 (40 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 19:5066 flights20.3%
Departs 19:4044 flights13.5%
Departs 20:1340 flights12.3%

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 19:50 departure sits in the 5pm–8pm window. Across every US flight scheduled in that window the on-time rate is 68.2%, and AA 2539 runs 8 points worse at 60.3%. 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 2539 next to MIA to BOS

Every carrier on MIA to BOS combined arrived on time 69.7% of the time across 3,415 flights, so AA 2539 is 9 points behind it. American flew 2,230 flights on the same city pair under all its flight numbers, including this one, and those ran 70.7% on time. Across its whole network American Airlines managed 74.4%, which this flight trails by 14 points.

AA 2539 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
AA 2539thin sample	325	60.3%	78 min	2.15%	D
All American Airlines on MIA–BOS	2,230	70.7%	71 min	1.75%	C
All carriers on MIA–BOS	3,415	69.7%	73 min	2.40%	C
American Airlines, whole network	986,297	74.4%	85 min	2.29%	C

Across the year

AA 2539 quarter by quarter

AA 2539 did not run the same all year. Its best quarter was Oct–Dec 2025 at 73.3% on time and its weakest Jan–Mar 2026 at 54.4%, a swing of 19 points on roughly 81 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 202588 flights55.2%
Oct–Dec 202561 flights73.3%
Jan–Mar 202685 flights54.4%
Apr–Jun 202691 flights61.5%

Scale runs 45% to 80%. Rows with fewer than 30 flights show a dash.

By weekday, AA 2539 did best on Saturday at 69.8% on time and worst on Friday at 55.3%. Each day rests on about 46 flights, so a gap of 15 points is worth noticing but could still narrow in another year.

Delay causes

Why AA 2539 runs late

One category carries most of the weight here. Late-arriving aircraft accounts for 43% of the 9,868 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
42%
National Airspace System
12%
Extreme weather
3%

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 9,868 reported delay minutes here, that single category outweighs weather by 15 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 9,868 delay minutes reported on AA 2539.

Cancellations sit at 2.15% against a national 1.81%, which is ordinary. Diversions add another 0.31%.

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. 17.0% 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.

The 1,258 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.

The same number turns up on two other city pairs in the data, including LAX to CMH (30) and CMH to LAX (30), but none flew often enough under AA 2539 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to MIA to BOS only.

One caution: this is a thin sample. 325 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 2539

For a booking, AA 2539 is a flight to put a long connection behind. 17.0% of its completed flights arrived an hour or more late, which a short layover will not absorb. If the onward flight is on a separate ticket, the risk sits with you.

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