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DelayAtlas

Carrier route record

UABNAORD

United Airlines · Nashville to Chicago

Flights
1,380
Period
July 2025 to June 2026
Share of route
27%
Carriers
9
CGRADE

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

United on BNA to ORD sits in the middle of the pack with a C. About seven flights in ten arrive on time by the DOT's definition, 5 points worse than the national rate of 77.6%. The late ones land an hour and a half behind schedule. That rests on 1,380 flights. The strongest carrier on the route with a full sample, Republic Airways, flew 562 at 73.4% on time.

Republic Airways is the most reliable of the four carriers covered here at 73.4% on time across 562 flights.

Key figures

On time

72.3%

Arrivals under 15 minutes late, of 1,348 completed flights

Avg delay

93 min

Across delayed arrivals only, not all flights

Cancelled

2.10%

National rate is 1.81%

Whole route

70.4%

Every carrier on BNA to ORD, 5,024 flights

These figures cover 1,380 flights between July 2025 and June 2026. Beyond the headline rate, 10.9% 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

United against every carrier on BNA to ORD

United flew 1,380 of the 5,024 flights on BNA to ORD, about 27% of it. Its 72.3% on time is 2 points better than the route as a whole, which runs 70.4%. Ranked by on-time rate it is number four of nine carriers on the route, where the range runs from Southwest at 76.7% to American at 65.5%. Four of those carriers flew fewer than 365 flights here, so treat their positions as rough.

The choice of carrier is not cosmetic here. Republic Airways arrives on time 73.4% of the time; American Airlines manages 65.5%. Sample sizes sit next to every figure, because a two-point gap across 384 flights means less than a ten-point one.

On-time performance by carrier on BNA to ORD
AirlineFlightsOn timeAvg delayCancelledGrade
Southwest Airlinesthin sample33876.7%59 min1.48%B
Republic Airways56273.4%80 min2.14%C
Envoy Air78273.0%75 min3.84%C−
United Airlines (this page)1,38072.3%93 min2.10%C
Frontier Airlinesthin sample8167.9%82 min3.70%C−
Spirit Airlinesthin sample2766.7%45 min0.00%C+
PSA Airlinesthin sample366.7%30 min0.00%C+
SkyWest Airlines1,46765.9%102 min3.68%C−
American Airlines38465.5%120 min1.82%C

Envoy Air cancels 3.8% 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

When United runs best on this route

Departure time matters more here than the choice of carrier. The gap between the best and worst window is 29 points, against 8 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

  • 5am–8am307 flights79.5%
  • 8am–11am303 flights82.8%
  • 11am–2pm269 flights82.2%
  • 2pm–5pm247 flights58.0%
  • 5pm–8pm237 flights54.1%
  • 8pm–5am17 flights

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

The 5pm–8pm window is where this operation falls apart: 54.1% on time, against 82.8% 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 5am–8am window is the busiest, with 307 flights scheduled in it.

Across the year

United on BNA to ORD through the year

On-time rate by calendar month65J74F59M70A71M76J72J81A88S70O71N69D
Darker means more delays. Figures are on-time percentages.September best, March worst

September is the best month on the calendar at 88.3% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. April was the busiest month here, with 183 flights.

Across the week, Saturday is the strongest day at 78.9% on time and Thursday the weakest at 65.3%. 14 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week70.1Mon72.6Tue76.8Wed65.3Thu70.2Fri78.9Sat73.2Sun
Monday: 70.1 percent on time. Tuesday: 72.6 percent on time. Wednesday: 76.8 percent on time. Thursday: 65.3 percent on time. Friday: 70.2 percent on time. Saturday: 78.9 percent on time. Sunday: 73.2 percent on time

Delay causes

Why United runs late on this route

Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 35,000 reported delay minutes.

  • National Airspace System
    42%
  • Carrier
    32%
  • Late-arriving aircraft
    21%
  • Extreme weather
    5%

42% 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 15,000 minutes out of 35,000, against a national NAS share of 21%. The split is drawn from 34,821 reported delay minutes.

Cancellations sit at 2.10% against a national 1.81%, which is ordinary. Diversions add another 0.22%.

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. 10.9% 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 409 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 8am–11am window matters as much as it does.

The return leg runs 70.4% on time across 1,381 flights, within 2 points 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 1,380 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 United on BNA to ORD

Put together: the calendar is the biggest lever here, not the carrier or the hour. September runs 88.3% on time and March 59.1%, a swing of 29 points. If the dates move at all, move them out of March before you think about anything else. 1,348 completed flights over 12 months sit behind that.

Related

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.