Carrier route record
DLLAX→BOS
Delta Air Lines · Los Angeles to Boston
- Flights
- 1,230
- Period
- July 2025 to June 2026
- Share of route
- 26%
- Carriers
- 4
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Delta Air Lines.
Delta on LAX to BOS lands a B, about a point better than the national rate of 77.6%. About one flight in five arrives 15 minutes late or worse, and those flights are late by an hour and a half on average. That is a workable record, not a spotless one. That rests on 1,230 flights. The strongest carrier on the route with a full sample, United Airlines, flew 716 at 87.0% on time.
United Airlines is the most reliable of the three carriers covered here at 87.0% on time across 716 flights.
Key figures
On time
78.6%
Arrivals under 15 minutes late, of 1,207 completed flights
Avg delay
86 min
Across delayed arrivals only, not all flights
Cancelled
1.71%
National rate is 1.81%
Whole route
78.4%
Every carrier on LAX to BOS, 4,718 flights
These figures cover 1,230 flights between July 2025 and June 2026. Beyond the headline rate, 8.7% 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
Delta against every carrier on LAX to BOS
Delta flew 1,230 of the 4,718 flights on LAX to BOS, about 26% of it. Its 78.6% on time is about level with the route as a whole at 78.4%. Ranked by on-time rate it is number two of four carriers on the route, where the range runs from United at 87.0% to JetBlue at 75.8%.
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 (this page) | 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.
Flight by flight
Delta flight numbers on LAX to BOS
Departure window
When Delta runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 15 points, against 11 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am232 flights85.7%
- 8am–11am272 flights74.3%
- 11am–2pm219 flights70.8%
- 2pm–5pm229 flights76.1%
- 5pm–8pm—
- 8pm–5am278 flights85.2%
Scale runs 60% to 90%. 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 70.8% on time against 85.7% 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 278 flights scheduled in it.
Across the year
Delta on LAX to BOS through the year
Delays peak in October, when the on-time rate falls to 65.5%. August is the strongest month at 90.8%. Moving a flexible trip across that boundary buys 25 points. May was the busiest month here, with 119 flights.
Across the week, Friday is the strongest day at 81.9% on time and Sunday the weakest at 76.0%. 6 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Delta 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 22,000 reported delay minutes.
- 41%Carrier
- 31%National Airspace System
- 19%Late-arriving aircraft
- 9%Extreme weather
- 0%Security
The largest share of delay minutes, 41%, 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 9,076 of the 22,000 delay minutes reported here. The split is drawn from 22,158 reported delay minutes.
Cancellations sit at 1.71% against a national 1.81%, which is ordinary. Diversions add another 0.16%.
Connections and stage length
What a delay here costs
8.7% 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 last an hour and a half, 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 75.2% on time across 1,228 flights, 3 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 3 points of difference.
The sample behind these figures is 1,230 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 Delta on LAX to BOS
Put together: the calendar is the biggest lever here, not the carrier or the hour. August runs 90.8% on time and October 65.5%, a swing of 25 points. If the dates move at all, move them out of October before you think about anything else. 1,207 completed flights over 12 months sit behind that.
Related
Where to go next
- LAX to BOS, every carrier
- Delta on BOS to LAX, the return leg
- United Airlines on LAX to BOS87.0%
- American Airlines on LAX to BOS76.5%
- JetBlue Airways on LAX to BOS75.8%
- Delta Air Lines network-wide record
- Los Angeles International (LAX) delay statistics
- Boston Logan International (BOS) delay statistics
- Same route, different airline: where the carrier you pick matters most
- The best time of day to fly, according to 7.04 million flight records
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.