Carrier route record

DLBOS→AUS

Delta Air Lines · Boston to Austin

Flights: 1,001
Period: September 2025 to August 2026
Share of route: 58%
Carriers: 3

Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with Delta Air Lines.

Delta on BOS to AUS 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 an hour and a half behind schedule. That rests on 1,001 flights, with a median arrival 8 minutes early.

The US average over the same twelve months is 77.3%, so there is little to separate Delta on BOS to AUS from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.

On time

73.7%

Arrivals under 15 minutes late, of 973 completed flights

Avg delay

87 min

Across delayed arrivals only, not all flights

Cancelled

2.60%

National rate is 1.89%

Whole route

72.6%

Every carrier on BOS to AUS, 1,713 flights

These figures cover 1,001 flights between September 2025 and August 2026. Beyond the headline rate, 10.6% of arrivals land a full hour or more behind schedule, against 8.3% nationally.

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Carrier by carrier

Delta against every carrier on BOS to AUS

Delta flew 1,001 of the 1,713 flights on BOS to AUS, most of the route. Its 73.7% on time is about level with the route as a whole at 72.6%. Ranked by on-time rate it is number two of three carriers on the route, where the range runs from JetBlue at 74.9% to Southwest at 65.6%. One of those carriers flew fewer than 365 flights here, so treat their positions as rough.

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.

On-time performance by carrier on BOS to AUS
Airline	Flights	On time	Avg delay	Cancelled	Grade
JetBlue Airways	426	74.9%	61 min	2.58%	C
Delta Air Lines (this page)	1,001	73.7%	87 min	2.60%	C
Southwest Airlinesthin sample	286	65.6%	52 min	1.40%	C

Flight by flight

Delta flight numbers on BOS to AUS

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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 24 points, against half a point between the best and worst carrier.

5am–8am362 flights83.4%
8am–11am3 flights—
11am–2pm280 flights76.3%
2pm–5pm28 flights—
5pm–8pm326 flights59.5%
8pm–5am2 flights—

Scale runs 50% to 90%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 59.5% on time, against 83.4% 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 362 flights scheduled in it.

Across the year

Delta on BOS to AUS through the year

Darker means more delays. Figures are on-time percentages.April best, July worst

July is the worst month at 63.2% on time, 25 points below April, the best at 87.8%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. March was the busiest month here, with 89 flights.

Across the week, Wednesday is the strongest day at 78.8% on time and Sunday the weakest at 65.4%, a spread of 13 points.

Arrival by arrival

How late Delta on BOS to AUS runs when it is late

Delta on BOS to AUS often beats the schedule: 369 of 973 completed flights, 38%, arrived 15 minutes or more early. The 256 late arrivals split 71 under half an hour, 82 between 30 and 60 minutes, and 103 an hour or more.

15+ min early369 flights37.9%
Within 15 min348 flights35.8%
15–29 min late71 flights7.3%
30–59 min late82 flights8.4%
1–2 hours late53 flights5.4%
2+ hours late50 flights5.1%

Scale runs 0% to 100%.

Share of 973 completed flights by arrival against schedule.

33 of 223 late departures made up the time and arrived on time, 15% of them. In the other direction, 66 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 AUS.

The worst days

Worst days for Delta on BOS to AUS

The latest arrival of the period was on 25 September 2025, 19 hours 16 minutes behind schedule; most of its delay minutes were filed as national airspace system delay. Three of the five worst days fell in January 2026.

The latest arrivals of Delta on BOS to AUS in the period
Date	Arrived late by	Largest filed cause
25 September 2025	19 hours 16 minutes	National Airspace System
5 January 2026	15 hours 29 minutes	Carrier
9 February 2026	14 hours 57 minutes	Carrier
15 January 2026	13 hours 52 minutes	Carrier
19 January 2026	8 hours 19 minutes	Late-arriving aircraft

Delay causes

Why Delta runs late on this route

Carrier accounts for 44% of the 22,000 delay minutes carriers reported here, and the remaining four split what is left.

Carrier
44%
Late-arriving aircraft
32%
National Airspace System
22%
Extreme weather
3%

The largest share of delay minutes, 44%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 9,765 of the 22,000 delay minutes reported here. The split is drawn from 22,270 reported delay minutes.

The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 83.4% on time here.

Cancellations run at 2.60%, against 1.89% nationally. That is about one flight in 40 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.

Connections and stage length

What a delay here costs

10.6% 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 return leg is a different operation and performs like one: it runs 69.6% on time across 1,001 flights, 4 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 4 points of difference.

One caution: this is a thin sample. 1,001 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 Delta on BOS to AUS

Put together: treat all of this as provisional. 1,001 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 73.7% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 973 completed flights over 12 months sit behind that.

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures