Route reliability record
LAX→BOS
Los Angeles to Boston
- Flights
- 4,718
- Period
- July 2025 to June 2026
- Distance
- 2,611 mi
- Carriers
- 4
This route lands a B, about a point better than the national rate of 77.6%. About one flight in five arrive 15 minutes late or worse, and those flights are late by a little over an hour on average. That is a workable record, not a spotless one. That rests on 4,718 flights, of which United Airlines flew 716 at 87.0% on time.
United Airlines is the most reliable of the four carriers covered here at 87.0% on time across 716 flights.
Key figures
On time
78.4%
Arrivals under 15 minutes late, of 4,648 completed flights
Avg delay
81 min
Across delayed arrivals only, not all flights
Cancelled
1.42%
National rate is 1.81%
Best carrier
United
87.0% on time across 716 flights
These figures cover 4,718 flights between July 2025 and June 2026. Beyond the headline rate, 8.5% 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
Which airline is most reliable on LAX to BOS
The choice of carrier is not cosmetic here. United Airlines arrives on time 87.0% of the time; JetBlue Airways manages 75.8%. Sample sizes sit next to every figure, because a two-point gap across 1,626 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 716 | 87.0% | 70 min | 1.12% | A |
| Delta Air Lines | 1,230 | 78.6% | 86 min | 1.71% | B |
| American Airlines | 1,146 | 76.5% | 91 min | 1.31% | B |
| JetBlue Airways | 1,626 | 75.8% | 73 min | 1.41% | B |
United leads JetBlue by 11 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 19 points, against 11 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am609 flights88.2%
- 8am–11am1,324 flights75.6%
- 11am–2pm775 flights69.3%
- 2pm–5pm593 flights74.4%
- 5pm–8pm1 flights—
- 8pm–5am1,416 flights83.5%
Scale runs 60% to 95%. Rows with fewer than 30 flights show a dash.
The weak window here is the middle of the day, not the evening: 11am–2pm runs 69.3% on time against 88.2% for 5am–8am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 8pm–5am window is the busiest, with 1,416 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 16 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
Delays peak in October, when the on-time rate falls to 72.2%. August is the strongest month at 87.7%. Moving a flexible trip across that boundary buys 16 points. June was the busiest month here, with 453 flights.
Across the week, Saturday is the strongest day at 81.7% on time and Sunday the weakest at 73.7%. 8 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
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 81,000 reported delay minutes.
- 35%Late-arriving aircraft
- 34%Carrier
- 28%National Airspace System
- 3%Extreme weather
- 0%Security
35% 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 81,000 reported delay minutes here, that single category outweighs weather by 11 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 80,970 reported delay minutes.
The largest share of delay minutes, 34%, 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 28,000 of the 81,000 delay minutes reported here.
Cancellations sit at 1.42% against a national 1.81%, which is ordinary. Diversions add another 0.06%.
Connections and stage length
What a delay here actually costs
8.5% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route are the a little over an hour kind, which a normal layover absorbs.
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 is a different operation and performs like one: it runs 74.9% on time across 4,713 flights, 4 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 4 points of difference.
The sample behind these figures is 4,718 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 this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. August runs 87.7% on time and October 72.2%, a swing of 16 points. If the dates move at all, move them out of October before you think about anything else. 4,648 completed flights over 12 months sit behind that.
Common questions
LAX to BOS questions
How often is LAX to BOS delayed?
About one flight in five arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 21.6% of the 4,718 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on LAX to BOS?
United Airlines leads at 87.0% on time across 716 flights. JetBlue Airways is at the other end on 75.8%, a gap of 11 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on LAX to BOS?
The 5am–8am departure window is the strongest at 88.2% on time. The 11am–2pm window is the weakest at 69.3%, 19 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are October delays on LAX to BOS?
October is the weakest month at 72.2% on time, compared with 87.7% in August. Across the year that is 16 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- BOS to LAX — the return legseparate record
- Los Angeles International (LAX) delay statistics
- Boston Logan International (BOS) delay statistics
- United Airlines on-time record87.0%
- Delta Air Lines on-time record78.6%
- American Airlines on-time record76.5%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
Direction matters. LAX to BOS and BOS to LAX are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.