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DelayAtlas

Carrier route record

UAORDBTV

United Airlines · Chicago to Burlington

Flights
683
Period
July 2025 to June 2026
Share of route
55%
Carriers
4
C+GRADE

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

United on ORD to BTV 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 about an hour behind schedule. That rests on 683 flights, with a median arrival 1 minute early.

The national on-time rate over the same period is 77.6%, so United on ORD to BTV runs 5 points behind the country as a whole. Across a thousand flights that is about 50 extra late arrivals.

Key figures

On time

72.6%

Arrivals under 15 minutes late, of 674 completed flights

Avg delay

62 min

Across delayed arrivals only, not all flights

Cancelled

0.73%

National rate is 1.81%

Whole route

69.0%

Every carrier on ORD to BTV, 1,245 flights

These figures cover 683 flights between July 2025 and June 2026. Beyond the headline rate, 9.5% 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 ORD to BTV

United flew 683 of the 1,245 flights on ORD to BTV, most of the route. Its 72.6% on time is 4 points better than the route as a whole, which runs 69.0%. Ranked by on-time rate it is number two of four carriers on the route, where the range runs from Envoy at 82.5% to SkyWest at 62.0%. Two 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 ORD to BTV
AirlineFlightsOn timeAvg delayCancelledGrade
Envoy Airthin sample6382.5%36 min0.00%B+
United Airlines (this page)68372.6%62 min0.73%C+
Republic Airwaysthin sample1870.6%49 min5.56%C−
SkyWest Airlines48162.0%92 min3.74%D−

Flight by flight

United flight numbers on ORD to BTV

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 18 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.

  • 5am–8am19 flights
  • 8am–11am
  • 11am–2pm311 flights81.2%
  • 2pm–5pm2 flights
  • 5pm–8pm351 flights63.6%
  • 8pm–5am

Scale runs 55% to 85%. Rows with fewer than 30 flights show a dash.

The 5pm–8pm window is where this operation falls apart: 63.6% on time, against 81.2% for the 11am–2pm 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 5pm–8pm window is the busiest, with 351 flights scheduled in it.

Across the year

United on ORD to BTV through the year

On-time rate by calendar month65J60F71M66A74M72J64J83A77S84O71N80D
Darker means more delays. Figures are on-time percentages.October best, February worst

February is the weak month at 60.0% on time, against 83.9% in October. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. March was the busiest month here, with 62 flights.

Across the week, Tuesday is the strongest day at 77.1% on time and Thursday the weakest at 67.7%. 9 points is a smaller lever than departure hour, but it is free.

On-time rate by day of the week69.7Mon77.1Tue76.3Wed67.7Thu75.0Fri71.1Sat71.3Sun
Monday: 69.7 percent on time. Tuesday: 77.1 percent on time. Wednesday: 76.3 percent on time. Thursday: 67.7 percent on time. Friday: 75.0 percent on time. Saturday: 71.1 percent on time. Sunday: 71.3 percent on time

Delay causes

Why United runs late on this route

One category carries most of the weight here. Late-arriving aircraft accounts for 48% of the 12,000 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
    48%
  • Carrier
    26%
  • National Airspace System
    18%
  • Extreme weather
    7%

48% 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 12,000 reported delay minutes here, that single category outweighs weather by 7 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 11,504 reported delay minutes.

Cancellations are rare at 0.73%, below the national 1.81% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.

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. 9.5% 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 763 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 69.0% on time across 683 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. 683 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 United on ORD to BTV

Put together: treat all of this as provisional. 683 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 72.6% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 674 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.