Route reliability record
AUS→BOS
Austin to Boston
- Flights
- 1,634
- Period
- July 2025 to June 2026
- Distance
- 1,698 mi
- Carriers
- 3
This route draws a C. About 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 1,634 AUS to BOS flights, with a median arrival 2 minutes late.
Best time to fly AUS to BOS: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 87.6% of the time and Saturday flights 75.3%, against 65.4% for the route overall.
The national on-time rate over the same period is 77.6%, so this route runs 12 points behind the country as a whole. Across a thousand flights that is about 122 extra late arrivals.
Key figures
On time
65.4%
Arrivals under 15 minutes late, of 1,592 completed flights
Avg delay
81 min
Across delayed arrivals only, not all flights
Cancelled
2.33%
National rate is 1.81%
Best carrier
Delta
70.9% on time across 988 flights
These figures cover 1,634 flights between July 2025 and June 2026. Beyond the headline rate, 14.5% 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 AUS to BOS
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Delta Air Lines | 988 | 70.9% | 91 min | 2.73% | C |
| JetBlue Airwaysthin sample | 364 | 58.9% | 84 min | 1.65% | D |
| Southwest Airlinesthin sample | 282 | 54.7% | 54 min | 1.77% | F |
Flight by flight
Flights on AUS to BOS
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.
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 36 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am346 flights87.6%
- 8am–11am108 flights73.8%
- 11am–2pm383 flights51.9%
- 2pm–5pm320 flights57.2%
- 5pm–8pm476 flights63.8%
- 8pm–5am1 flights—
Scale runs 45% 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 51.9% on time against 87.6% 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 5pm–8pm window is the busiest, with 476 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 21 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.
May is the best month on the calendar at 74.5% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. June was the busiest month here, with 162 flights.
Across the week, Saturday is the strongest day at 75.3% on time and Thursday the weakest at 57.5%. 18 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 45,000 reported delay minutes.
- 36%Late-arriving aircraft
- 33%National Airspace System
- 29%Carrier
- 1%Extreme weather
- 0%Security
36% 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 45,000 reported delay minutes here, that single category outweighs weather by 36 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 44,515 reported delay minutes.
33% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 15,000 minutes out of 45,000, against a national NAS share of 21%.
Cancellations sit at 2.33% against a national 1.81%, which is ordinary. Diversions add another 0.24%.
Connections and stage length
What a delay here actually costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 14.5% 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 1,698 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 72.2% on time across 1,634 flights, 7 points above 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 7 points of difference.
The sample behind these figures is 1,634 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 BOS 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 74.5% on time and October 53.3%, a swing of 21 points. If the dates move at all, move them out of October before you think about anything else. 1,592 completed flights over 12 months sit behind that.
Common questions
AUS to BOS questions
How often is AUS to BOS delayed?
About one flight in three arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 34.6% of the 1,634 flights in this analysis, against 22.4% nationally. Delayed flights are late by a little over an hour on average.
How reliable is AUS to BOS compared with the rest of the country?
65.4% of flights arrive on time here against a national 77.6%, a difference of 12 points against it. That is worth a C on this site's grading scale.
What time of day has the fewest delays on AUS to BOS?
The 5am–8am departure window is the strongest at 87.6% on time. The 11am–2pm window is the weakest at 51.9%, 36 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 AUS to BOS?
October is the weakest month at 53.3% on time, compared with 74.5% in May. Across the year that is 21 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 AUS — the return legseparate record
- Austin-Bergstrom International (AUS) delay statistics
- Boston Logan International (BOS) delay statistics
- Delta Air Lines on AUS to BOS70.9%
- JetBlue Airways on AUS to BOS58.9%
- Southwest Airlines on AUS to BOS54.7%
- AUS to DEN, a related route78.4%
- DCA to BOS, a related route71.4%
- AUS to DFW, a related route73.8%
- Delta Air Lines on-time record70.9%
- JetBlue Airways on-time record58.9%
- Southwest Airlines on-time record54.7%
- 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. AUS to BOS and BOS to AUS 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.