Route reliability record

AUS→ORD

Austin to Chicago

Flights: 3,166
Period: July 2025 to June 2026
Distance: 977 mi
Carriers: 6

This route sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 6 points worse than the national rate of 77.6%. The late ones land an hour and a half behind schedule. That rests on 3,166 flights, of which United Airlines flew 1,470 at 74.9% on time.

The national on-time rate over the same period is 77.6%, so this route runs 6 points behind the country as a whole. Across a thousand flights that is about 55 extra late arrivals.

On time

72.1%

Arrivals under 15 minutes late, of 3,077 completed flights

Avg delay

90 min

Across delayed arrivals only, not all flights

Cancelled

2.15%

National rate is 1.81%

Best carrier

United

74.9% on time across 1,470 flights

These figures cover 3,166 flights between July 2025 and June 2026. Beyond the headline rate, 11.1% 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 ORD

The two carriers here are closely matched: 5 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.

On-time performance by carrier on AUS to ORD
Airline	Flights	On time	Avg delay	Cancelled	Grade
United Airlines	1,470	74.9%	80 min	1.02%	C
Envoy Airthin sample	86	72.6%	62 min	2.33%	C
American Airlines	1,190	69.8%	105 min	3.11%	C−
Republic Airwaysthin sample	95	69.7%	71 min	6.32%	C−
Southwest Airlinesthin sample	207	68.8%	56 min	0.48%	C+
Frontier Airlinesthin sample	118	65.1%	141 min	5.93%	C−

American Airlines cancels 3.1% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.

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 32 points, against 5 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

5am–8am699 flights82.6%
8am–11am649 flights84.5%
11am–2pm725 flights73.1%
2pm–5pm465 flights59.2%
5pm–8pm582 flights55.9%
8pm–5am46 flights52.5%

Scale runs 45% to 90%. Rows with fewer than 30 flights show a dash.

The 8pm–5am window is where this operation falls apart: 52.5% on time, against 84.5% for the 8am–11am 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 11am–2pm window is the busiest, with 725 flights scheduled in it.

Across the year

When delays peak on this route

This route's year swings by 15 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.

Darker means more delays. Figures are on-time percentages.May best, March worst

May is the best month on the calendar at 79.1% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. March was the busiest month here, with 302 flights.

Across the week, Tuesday is the strongest day at 77.6% on time and Sunday the weakest at 67.1%. 11 points is a smaller lever than departure hour, but it is free.

Delay causes

Why this route gets delayed

One category carries most of the weight here. Late-arriving aircraft accounts for 44% of the 78,000 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.

Late-arriving aircraft
44%
National Airspace System
34%
Carrier
20%
Extreme weather
2%
Security
0%

44% 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 78,000 reported delay minutes here, that single category outweighs weather by 22 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 77,574 reported delay minutes.

34% 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 26,000 minutes out of 78,000, against a national NAS share of 21%.

Cancellations sit at 2.15% against a national 1.81%, which is ordinary. Diversions add another 0.66%.

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. 11.1% 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 977 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 runs 72.0% on time across 3,169 flights, within half a point of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.

The sample behind these figures is 3,166 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.

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 79.1% on time and March 64.5%, a swing of 15 points. If the dates move at all, move them out of March before you think about anything else. 3,077 completed flights over 12 months sit behind that.

Common questions

AUS to ORD questions

How often is AUS to ORD delayed?

Roughly one flight in four arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 27.9% of the 3,166 flights in this analysis, against 22.4% nationally. Delayed flights are late by an hour and a half on average.

Which airline is most reliable on AUS to ORD?

United Airlines leads at 74.9% on time across 1,470 flights. American Airlines is at the other end on 69.8%, a gap of 5 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.

What time of day has the fewest delays on AUS to ORD?

The 8am–11am departure window is the strongest at 84.5% on time. The 8pm–5am window is the weakest at 52.5%, 32 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 March delays on AUS to ORD?

March is the weakest month at 64.5% on time, compared with 79.1% in May. Across the year that is 15 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.

Where to go next

Direction matters. AUS to ORD and ORD to AUS are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.

Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.

Key figures