Route reliability record
BOS→LAX
Boston to Los Angeles
- Flights
- 4,794
- Period
- September 2025 to August 2026
- Distance
- 2,611 mi
- Carriers
- 4
This route 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 77.3%. The late ones land a little over an hour behind schedule. That rests on 4,794 BOS to LAX flights, of which United Airlines flew 731 at 76.8% on time.
Best time to fly BOS to LAX: a 5am–8am departure, ideally on a Wednesday. Flights in that window arrived on time 84.1% of the time and Wednesday flights 76.3%, against 73.7% for the route overall.
United Airlines is the most reliable of the four carriers covered here at 76.8% on time across 731 flights.
Key figures
On time
73.7%
Arrivals under 15 minutes late, of 4,697 completed flights
Avg delay
79 min
Across delayed arrivals only, not all flights
Cancelled
1.81%
National rate is 1.89%
Best carrier
United
76.8% on time across 731 flights
These figures cover 4,794 flights between September 2025 and August 2026. Beyond the headline rate, 9.5% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Which airline is most reliable on BOS to LAX
The four carriers here are closely matched: 5 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.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 731 | 76.8% | 71 min | 1.09% | B |
| Delta Air Lines | 1,238 | 73.9% | 74 min | 2.18% | C |
| American Airlines | 1,183 | 73.6% | 96 min | 1.61% | C |
| JetBlue Airways | 1,642 | 72.2% | 73 min | 2.01% | C |
No carrier stands out. United tops the table at 76.8%, 5 points clear of the bottom, which is inside the range this kind of sample moves year to year.
Flight by flight
Flights on BOS to LAX
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Best ways to make this trip
The most reliable ways to fly Boston to Los Angeles
Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. BOS → LAXBoston to Los Angeles | United Airlines | 76.0% | 76.8% | 1.09% | 11am–2pm, Tue | — |
| 2. BOS → LAXBoston to Los Angeles | American Airlines | 72.4% | 73.6% | 1.61% | 5am–8am, Wed | — |
| 3. BOS → LAXBoston to Los Angeles | Delta Air Lines | 72.3% | 73.9% | 2.18% | 8am–11am, Fri | DL 479 06:15 |
| 4. BOS → LAXBoston to Los Angeles | JetBlue Airways | 70.7% | 72.2% | 2.01% | 5am–8am, Wed | B6 287 06:00 |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
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 27 points, against 5 points between the best and worst carrier.
- 5am–8am1,171 flights84.1%
- 8am–11am888 flights78.8%
- 11am–2pm548 flights79.3%
- 2pm–5pm630 flights72.7%
- 5pm–8pm1,087 flights63.3%
- 8pm–5am470 flights57.2%
Scale runs 50% to 90%.
The 8pm–5am window is where this operation falls apart: 57.2% on time, against 84.1% 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 5am–8am window is the busiest, with 1,171 flights scheduled in it.
Explore
Filter BOS to LAX by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On BOS to LAX, the best departure window is 5am–8am at 84.1% on time and the worst is 8pm–5am at 57.2%, a wide gap of 26.9 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am84.1%
- 8–11am78.8%
- 11am–2pm79.3%
- 2–5pm72.7%
- 5–8pm63.3%
- 8pm–5am57.2%
best all US flightsScale 50% to 95%.
Across the year
When delays peak on this route
This route's year swings by 22 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.
December is the weak month at 62.1% on time, against 84.4% in May. 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. July was the busiest month here, with 484 flights.
Across the week, Wednesday is the strongest day at 76.3% on time and Monday the weakest at 70.8%, a spread of 6 points.
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 97,000 reported delay minutes.
- 42%Late-arriving aircraft
- 35%Carrier
- 21%National Airspace System
- 2%Extreme weather
- 0%Security
42% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 97,000 reported delay minutes here, that single category outweighs weather by 18 to one. The split is drawn from 97,036 reported delay minutes.
The largest share of delay minutes, 35%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 34,000 of the 97,000 delay minutes reported here.
Cancellations sit at 1.81% against a national 1.89%, which is ordinary. Diversions add another 0.21%.
Connections and stage length
What a delay here actually costs
9.5% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection 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 76.2% on time across 4,797 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 4,794 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.
Work out the risk of missing a connection in LAX after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. May runs 84.4% on time and December 62.1%, a swing of 22 points. If the dates move at all, move them out of December before you think about anything else. 4,697 completed flights over 12 months sit behind that.
Common questions
BOS to LAX questions
How often is BOS to LAX delayed?
About one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 26.3% of the 4,794 flights in this analysis, against 22.7% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on BOS to LAX?
United Airlines leads at 76.8% on time across 731 flights. JetBlue Airways is at the other end on 72.2%, a gap of 5 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 BOS to LAX?
The 5am–8am departure window is the strongest at 84.1% on time. The 8pm–5am window is the weakest at 57.2%, 27 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 December delays on BOS to LAX?
December is the weakest month at 62.1% on time, compared with 84.4% in May. Across the year that is 22 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
- LAX to BOS — the return legseparate record
- Boston Logan International (BOS) delay statistics
- Los Angeles International (LAX) delay statistics
- United Airlines on BOS to LAX76.8%
- Delta Air Lines on BOS to LAX73.9%
- American Airlines on BOS to LAX73.6%
- JetBlue Airways on BOS to LAX72.2%
- BOS to DCA, a related route72.6%
- SFO to LAX, a related route70.9%
- BOS to ORD, a related route71.9%
- United Airlines on-time record76.8%
- Delta Air Lines on-time record73.9%
- American Airlines on-time record73.6%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Direction matters. BOS to LAX and LAX to BOS are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.