Carrier route record

DLMIA→AUS

Delta Air Lines · Miami to Austin

Flights: 222
Period: July 2025 to June 2026
Share of route: 10%
Carriers: 5

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

Delta on MIA to AUS sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 9 points worse than the national rate of 77.6%. The late ones land an hour and a half behind schedule. That rests on 222 flights, with a median arrival 2 minutes early.

The national on-time rate over the same period is 77.6%, so Delta on MIA to AUS runs 9 points behind the country as a whole. Across a thousand flights that is about 85 extra late arrivals.

On time

69.1%

Arrivals under 15 minutes late, of 220 completed flights

Avg delay

94 min

Across delayed arrivals only, not all flights

Cancelled

0.90%

National rate is 1.81%

Whole route

72.8%

Every carrier on MIA to AUS, 2,161 flights

These figures cover 222 flights between July 2025 and June 2026. Beyond the headline rate, 13.6% 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 MIA to AUS

Delta flew 222 of the 2,161 flights on MIA to AUS, about 10% of it. Its 69.1% on time is 4 points worse than the route as a whole, which runs 72.8%. Ranked by on-time rate it is last of five carriers on the route, where the range runs from Frontier at 82.6% to Delta at 69.1%. Three 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 MIA to AUS
Airline	Flights	On time	Avg delay	Cancelled	Grade
Frontier Airlinesthin sample	46	82.6%	97 min	0.00%	B+
American Airlines	1,523	73.8%	76 min	1.31%	C
Envoy Airthin sample	22	72.7%	47 min	0.00%	C+
Southwest Airlinesthin sample	348	69.2%	48 min	0.29%	C+
Delta Air Lines (this page)thin sample	222	69.1%	94 min	0.90%	C+

Departure window

When Delta runs best on this route

Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 222 flights.

There are not enough flights in each departure window to split Delta's MIA to AUS record by time of day without the percentages moving on noise. The headline rate of 69.1% is the reliable figure here.

Across the year

Delta on MIA to AUS through the year

Oct–Dec 202541 flights75.6%
Jan–Mar 202690 flights67.4%
Apr–Jun 202691 flights67.8%

Scale runs 60% to 80%. Rows with fewer than 30 flights show a dash.

Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 69.1% on time across 222 flights.

Quarter by quarter Delta on MIA to AUS held fairly steady: 75.6% in Oct–Dec 2025, 67.4% in Jan–Mar 2026 and 67.8% in Apr–Jun 2026. A spread of 8 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.

Across the week, Thursday is the strongest day at 87.1% on time and Sunday the weakest at 41.9%. 45 points is a smaller lever than departure hour, but it is free.

Delay causes

Why Delta runs late on this route

One category carries most of the weight here. Carrier accounts for 48% of the 6,357 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.

Carrier
48%
Late-arriving aircraft
38%
National Airspace System
12%
Extreme weather
2%

38% 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 6,357 reported delay minutes here, that single category outweighs weather by 16 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 6,357 reported delay minutes.

The largest share of delay minutes, 48%, 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 3,068 of the 6,357 delay minutes reported here.

Cancellations sit at 0.90% against a national 1.81%, which is ordinary. Diversions add another 0.00%.

Connections and stage length

What a delay here costs

For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 13.6% 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.

The 1,103 miles between these two airports put this in the middle of the US network, around two and a half to three hours of block time. That is enough cruise to absorb a ten-minute late pushback and not enough to absorb thirty. It is also long enough that the aircraft usually flies three or four legs a day rather than six, which slows how fast delay compounds.

The return leg is a different operation and performs like one: it runs 89.4% on time across 221 flights, 20 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 20 points of difference.

One caution: this is a thin sample. 222 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 MIA to AUS

Put together: treat all of this as provisional. 222 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 69.1% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 220 completed flights over 12 months sit behind that.

Where to go next

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