Illinois

What the Data Says About Flying in Illinois

Illinois (IL) has 10 airports tracked in the Bureau of Transportation Statistics on-time performance dataset, which together handled 4,168,274 flights. Across those flights, the statewide on-time rate comes in at 80.5%, with 51,535 cancellations producing a 1.24% cancellation rate. The average delay when a flight runs late is 2.9 minutes. Together these numbers are the most useful summary of what air travel through Illinois airports looks like in aggregate, and they provide the baseline for comparing individual airports against each other and against national averages.

The busiest airport in Illinois is Chicago, IL (ORD) in Chicago, which handled 3,114,086 flights at a 81% on-time rate and an average delay of 81.9 minutes. On the reliability front, Bloomington/Normal, IL (BMI) posts the highest on-time rate at 85.2% across 25,097 flights — worth comparing if you have flexibility on origin or destination airport within Illinois. Performance can differ sharply between a state's biggest hub and its smaller airports, so airport-level pages are the right place to dig into specifics.

Why the spread? Delays in Illinois — as everywhere in the BTS dataset — break down into five categories: late-arriving aircraft, carrier issues like maintenance and crew, National Aviation System constraints such as air traffic control and airspace congestion, weather, and security. The relative mix changes by airport and season: a small regional airport may see weather dominate, while a major hub tends to lean on late-aircraft and NAS delays. For travelers choosing flights through Illinois, the combination of a 80.5% statewide on-time rate, 2.9-minute average delay, and 1.24% cancellation rate is the concrete benchmark to weigh against specific airports and carriers.