Flight number record
DL 1156
Delta Air Lines · Austin to Boston
- Route
- AUS → BOS
- Departs
- 14:25
- Flights
- 306
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s DL 1156, check with Delta Air Lines.
DL 1156 earns an F, which is as low as this site's scale goes for a reason. Only 53.8% of flights arrive inside the 15-minute window, 24 points worse than the national rate of 77.3%. Late arrivals average an hour and a half. Treat any tight connection here as a coin flip. That rests on 306 flights, with a median arrival 11 minutes late.
The national on-time rate over the same period is 77.3%, so DL 1156 runs 24 points behind the country as a whole. Across a thousand flights that is about 235 extra late arrivals.
Key figures
On time
53.8%
Arrivals under 15 minutes late, of 301 completed flights
Avg delay
93 min
Across delayed arrivals only, not all flights
Cancelled
1.31%
National rate is 1.89%
1 hour+ late
22.9%
National rate is 8.3%
These figures cover 306 flights between September 2025 and August 2026. Beyond the headline rate, 22.9% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When DL 1156 flies
DL 1156 flies AUS to BOS without a single fixed slot. Its most common scheduled departure was 14:25, used on 61 of 306 flights, with 13:55 (51 flights) and 14:30 (32 flights) next.
- Departs 14:2561 flights19.9%
- Departs 13:5551 flights16.7%
- Departs 14:3032 flights10.5%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 14:25 departure sits in the 2pm–5pm window. Across every US flight scheduled in that window the on-time rate is 71.9%, and DL 1156 runs 18 points worse at 53.8%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.
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Against the route
DL 1156 next to AUS to BOS
Every carrier on AUS to BOS combined arrived on time 64.5% of the time across 1,713 flights, so DL 1156 is 11 points behind it. Delta flew 1,001 flights on the same city pair under all its flight numbers, including this one, and those ran 69.6% on time. Across its whole network Delta Air Lines managed 81.1%, which this flight trails by 27 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| DL 1156thin sample | 306 | 53.8% | 93 min | 1.31% | F |
| All Delta Air Lines on AUS–BOS | 1,001 | 69.6% | 90 min | 2.70% | C |
| All carriers on AUS–BOS | 1,713 | 64.5% | 80 min | 2.69% | D |
| Delta Air Lines, whole network | 1,039,517 | 81.1% | 71 min | 1.74% | B |
Across the year
DL 1156 quarter by quarter
DL 1156 did not run the same all year. Its best quarter was Apr–Jun 2026 at 63.3% on time and its weakest Jul–Sep 2025 at 26.7%, a swing of 37 points on roughly 61 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
- Jul–Sep 202530 flights26.7%
- Oct–Dec 202574 flights50.7%
- Jan–Mar 202649 flights63.0%
- Apr–Jun 202691 flights63.3%
- Jul–Sep 202662 flights50.0%
Scale runs 20% to 70%.
By weekday, DL 1156 did best on Saturday at 65.8% on time and worst on Thursday at 45.2%. Each day rests on about 44 flights, so a gap of 21 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late DL 1156 runs when it is late
The 139 late arrivals split 28 under half an hour, 42 between 30 and 60 minutes, and 69 an hour or more.
- 15+ min early50 flights16.6%
- Within 15 min112 flights37.2%
- 15–29 min late28 flights9.3%
- 30–59 min late42 flights14.0%
- 1–2 hours late43 flights14.3%
- 2+ hours late26 flights8.6%
Scale runs 0% to 100%.
Share of 301 completed flights by arrival against schedule.
Time lost at the gate mostly stays lost. Of 123 departures that left 15 minutes late or more, only 7 made it up before arrival. In the other direction, 23 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at BOS.
The worst days
Worst days for DL 1156
The latest arrival of the period was on 17 April 2026, 16 hours 45 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 17 April 2026 | 16 hours 45 minutes | Carrier |
| 20 November 2025 | 8 hours 42 minutes | Late-arriving aircraft |
| 21 May 2026 | 8 hours 32 minutes | Carrier |
| 25 September 2025 | 5 hours 17 minutes | National Airspace System |
| 15 March 2026 | 5 hours 9 minutes | Carrier |
Delay causes
Why DL 1156 runs late
National Airspace System accounts for 46% of the 13,000 delay minutes carriers reported here, and the remaining four split what is left.
- 46%National Airspace System
- 30%Carrier
- 23%Late-arriving aircraft
- 2%Extreme weather
46% 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 5,910 minutes out of 13,000, against a national NAS share of 21%. The split is drawn from 12,954 delay minutes reported on DL 1156.
Cancellations sit at 1.31% against a national 1.89%, which is ordinary. Diversions add another 0.33%.
Connections and routes
What a delay on this flight costs
22.9% 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 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 same number turns up on three other city pairs in the data, including TYS to ATL (24), ATL to TYS (13) and DTW to RSW (9), but none flew often enough under DL 1156 to report a rate for. Carriers move flight numbers between routes, so the figures on this page apply to AUS to BOS only.
One caution: this is a thin sample. 306 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking DL 1156
For a booking, DL 1156 is a flight to put a long connection behind. 22.9% of its completed flights arrived an hour or more late, which a short layover will not absorb. If the onward flight is on a separate ticket, the risk sits with you.
Related
Where to go next
- AUS to BOS, every carrier and departure
- BOS to AUS, the return direction
- Delta Air Lines 2098 on the same route87.5%
- Austin-Bergstrom International (AUS) delay statistics
- Boston Logan International (BOS) delay statistics
- Delta Air Lines on-time record
- Every Delta Air Lines flight number with a record
- The most and least reliable flight numbers in the US
- The best time of day to fly, according to 7.05 million flight records
A flight number here means Delta Air Lines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.
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.