Carrier route record

AABOS→LAX

American Airlines · Boston to Los Angeles

Flights: 1,143
Period: July 2025 to June 2026
Share of route: 24%
Carriers: 4

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

American on BOS to LAX sits in the middle of the pack with a C. Close to three flights in four arrive on time by the DOT's definition, 4 points worse than the national rate of 77.6%. The late ones land an hour and a half behind schedule. That rests on 1,143 flights. The strongest carrier on the route with a full sample, United Airlines, flew 716 at 76.8% on time.

United Airlines is the most reliable of the three carriers covered here at 76.8% on time across 716 flights.

On time

74.0%

Arrivals under 15 minutes late, of 1,125 completed flights

Avg delay

91 min

Across delayed arrivals only, not all flights

Cancelled

1.31%

National rate is 1.81%

Whole route

74.9%

Every carrier on BOS to LAX, 4,713 flights

These figures cover 1,143 flights between July 2025 and June 2026. Beyond the headline rate, 9.5% 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 BOS to LAX

American flew 1,143 of the 4,713 flights on BOS to LAX, about 24% of it. Its 74.0% on time is about level with the route as a whole at 74.9%. Ranked by on-time rate it is last of four carriers on the route, where the range runs from United at 76.8% to American at 74.0%.

The three carriers here are closely matched: 2 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.

On-time performance by carrier on BOS to LAX
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlines	716	76.8%	67 min	1.12%	B
Delta Air Lines	1,228	75.2%	76 min	1.71%	B
JetBlue Airways	1,626	74.5%	71 min	1.41%	C
American Airlines (this page)	1,143	74.0%	91 min	1.31%	C

No carrier stands out. United tops the table at 76.8%, 2 points clear of the bottom, which is inside the range this kind of sample moves year to year.

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 21 points, against 2 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am125 flights85.1%
8am–11am341 flights78.3%
11am–2pm218 flights77.9%
2pm–5pm77 flights72.0%
5pm–8pm361 flights63.7%
8pm–5am21 flights—

Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 63.7% on time, against 85.1% for the 5am–8am slot. By evening the aircraft flying these rotations have absorbed a full day of small delays and there is no slack left to recover in. The 5pm–8pm window is the busiest, with 361 flights scheduled in it.

Across the year

American on BOS to LAX through the year

Darker means more delays. Figures are on-time percentages.April best, December worst

December is the weak month at 59.1% on time, against 92.0% 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. March was the busiest month here, with 121 flights.

Across the week, Wednesday is the strongest day at 80.0% on time and Friday the weakest at 68.1%. 12 points is a smaller lever than departure hour, but it is free.

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 27,000 reported delay minutes.

Late-arriving aircraft
41%
Carrier
40%
National Airspace System
15%
Extreme weather
4%
Security
0%

41% 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 27,000 reported delay minutes here, that single category outweighs weather by 12 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 26,636 reported delay minutes.

The largest share of delay minutes, 40%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 11,000 of the 27,000 delay minutes reported here.

Cancellations sit at 1.31% against a national 1.81%, which is ordinary. Diversions add another 0.26%.

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. 9.5% 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 2,611 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 runs 76.5% on time across 1,146 flights, within 3 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

The sample behind these figures is 1,143 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 BOS to LAX

Put together: the calendar is the biggest lever here, not the carrier or the hour. April runs 92.0% on time and December 59.1%, a swing of 33 points. If the dates move at all, move them out of December before you think about anything else. 1,125 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