Flight number record

DL 1156

Delta Air Lines · Austin to Boston

Route: AUS → BOS
Departs: 14:25
Flights: 305
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s DL 1156, check with Delta Air Lines.

DL 1156 earns a D, which is as low as this site's scale goes for a reason. Only 56.5% of flights arrive inside the 15-minute window, 21 points worse than the national rate of 77.6%. Late arrivals average an hour and a half. Treat any tight connection here as a coin flip. That rests on 305 flights, with a median arrival 9 minutes late.

The national on-time rate over the same period is 77.6%, so DL 1156 runs 21 points behind the country as a whole. Across a thousand flights that is about 211 extra late arrivals.

On time

56.5%

Arrivals under 15 minutes late, of 299 completed flights

Avg delay

98 min

Across delayed arrivals only, not all flights

Cancelled

1.64%

National rate is 1.81%

1 hour+ late

22.4%

National rate is 8.1%

These figures cover 305 flights between July 2025 and June 2026. Beyond the headline rate, 22.4% 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.

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 55 of 305 flights, with 13:55 (51 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 14:2555 flights18.0%
Departs 13:5551 flights16.7%

Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.

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 72.4%, and DL 1156 runs 16 points worse at 56.5%. Midday slots inherit some of the morning's delays without yet carrying the full weight of the evening's.

Against the route

DL 1156 next to AUS to BOS

Every carrier on AUS to BOS combined arrived on time 65.4% of the time across 1,634 flights, so DL 1156 is 9 points behind it. Delta flew 988 flights on the same city pair under all its flight numbers, including this one, and those ran 70.9% on time. Across its whole network Delta Air Lines managed 81.6%, which this flight trails by 25 points.

DL 1156 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
DL 1156thin sample	305	56.5%	98 min	1.64%	D
All Delta Air Lines on AUS–BOS	988	70.9%	91 min	2.73%	C
All carriers on AUS–BOS	1,634	65.4%	81 min	2.33%	C
Delta Air Lines, whole network	1,038,570	81.6%	71 min	1.62%	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 Oct–Dec 2025 at 50.7%, a swing of 13 points on roughly 76 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 202591 flights51.1%
Oct–Dec 202574 flights50.7%
Jan–Mar 202649 flights63.0%
Apr–Jun 202691 flights63.3%

Scale runs 40% to 70%. Rows with fewer than 30 flights show a dash.

By weekday, DL 1156 did best on Saturday at 71.1% on time and worst on Thursday at 46.3%. Each day rests on about 44 flights, so a gap of 25 points is worth noticing but could still narrow in another year.

Delay causes

Why DL 1156 runs late

One category carries most of the weight here. National Airspace System accounts for 43% of the 13,000 delay minutes carriers reported, and the remaining four split what is left. The split is by minutes rather than by flights, so a few very long delays count for as much as many short ones.

National Airspace System
43%
Carrier
33%
Late-arriving aircraft
23%
Extreme weather
2%

43% 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 5,420 minutes out of 13,000, against a national NAS share of 21%. The split is drawn from 12,731 delay minutes reported on DL 1156.

Cancellations sit at 1.64% against a national 1.81%, which is ordinary. Diversions add another 0.33%.

Connections and routes

What a delay on this flight costs

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 22.4% 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 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. 305 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. 22.4% 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.

Where to go next

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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.

Key figures