Denver (DEN) and Chicago (ORD): July 2026 on-time record

Across both directions, 68.6% of the 1,105 flights between Denver and Chicago arrived on time in July 2026, within a few points of the national share of 69.4%. One month of data cannot separate a gap that small, so the pair is best read as average.

This pair was dominated by one operator: United Airlines alone flew 66.3% of all flights, more than half.

There was no clear winner among airlines. In at least one direction the top two finished within a few points of each other, which one month of data cannot separate, so the order below is not a verdict.

The National Aviation System (NAS) was the biggest source of attributed delay minutes for flights between Denver and Chicago, at 42.7%, unlike the national total for July 2026, where Late-arriving aircraft led.

One direction trailed a little. Flights from Denver to Chicago ran on time less often, 64.2% of 553 against 73.0% of 552 the other way, a gap under 10 points that one month of data can still separate.

2 airlines flew this pair often enough to be ranked in at least one direction. Each is set against the pair's combined figure below, so the comparison is among a small field.

United Airlines dominated this pair, flying more than half of all its flights, 733 in all, and 71.9% of them arrived on time, level with the pair's combined 68.6%, give or take a few points. Every other airline here was a junior partner.

With at least a quarter of the pair's flights, American Airlines put 67.4% of its 310 on time, level with the pair's combined 68.6%, give or take a few points.

Also flew this pair, too few flights to rank: Frontier Airlines (62 flights).

Of the 27 routes out of DEN that carried at least 300 flights in July 2026, the route to ORD placed in the bottom third for on-time arrivals.

Of the 36 routes out of ORD that carried at least 300 flights in July 2026, the route to DEN placed in the top third for on-time arrivals.

The two directions disagreed on the leading cause: National Aviation System (NAS) led on flights from Denver, while Late-arriving aircraft led on flights from Chicago.

With NAS delays the largest cause, extreme weather added 3.5% of the attributed minutes for flights between Denver and Chicago, close to its national share of 6.4%.

Behind the NAS figure, NAS delays pulled ahead of air carrier delays for flights between Denver and Chicago, 42.7% against 17.0%, a different order from the national figures.

National Aviation System (NAS) supplied 42.7% of the attributed delay minutes for flights between Denver and Chicago, a clear lead but short of a near-majority, with the rest spread over the other causes.

Second on the list, late-arriving aircraft added 36.8% of the attributed delay minutes for flights between Denver and Chicago.

Delay causes are shares of the delay minutes BTS attributes to flights that arrived 15 minutes or more late, not shares of flights. Extreme weather here means BTS's extreme-weather category only; milder weather delays are generally reported under NAS.

A flight counts as on time unless it arrives 15 minutes or more late. Cancelled and diverted flights count as not on time.

Directions are shown only with at least 500 flights, and an airline is ranked only with at least 100 flights in a direction; airlines below that are listed by name, not ranked.

A difference of a few points between two airlines, or between two directions, is within what one month of data can move. These figures describe July 2026 only.

These are figures for one month, July 2026, not a trend or forecast.

Source: US Department of Transportation, Bureau of Transportation Statistics, Reporting Carrier On-Time Performance, July 2026, as loaded by BookWithAI.