74% of flights from Missoula to Chicago arrived on time over the past 12 months. That is worse than the typical U.S. route. The 1 p.m. departures ran on time 73% of the time; the noon ones 72%. Most reliable airline: American Airlines (74%). 14% of flights arrived more than an hour late or not at all.
How late?
The on-time rate treats a flight 20 minutes late the same as one 5 hours late. Here's the split for MSO → ORD: when a flight was late, it was under 45 minutes late 42% of the time. About 1 in 9 flights landed an hour or more late, and 1 in 30 three hours or more; 0.8% were cancelled outright.
- On time or early74%
- 15–30 min late7.2%
- 30–60 min late5.1%
- 1–2 hours late5.7%
- 2–3 hours late2.3%
- 3+ hours late3.4%
- Diverted1.5%
- Cancelled0.8%
Share of all 473 scheduled flights, past 12 months, by arrival time against schedule.
By airline
| Airline | Flights | On time | Cancelled | Typical arrival | 1h+ late | Avg when late | Operated by |
|---|---|---|---|---|---|---|---|
| American Airlines | 316 | 74% | 0.0% | −8 min | 11.4% | +89 min | Envoy |
| United Airlines | 157 | 73% | 2.5% | −2 min | 11.5% | +102 min | United Airlines 53%, SkyWest 47% |
Airline = the name on the ticket. Regional flights (e.g. "Delta Connection") count under the ticketing airline, and the operator is listed.
Best time of day to fly
On-time rate by scheduled departure hour (local time at MSO). Delays build through the day as late planes knock on, so early flights usually do best.
By airline and hour
| Departs | American Airlines | United Airlines |
|---|---|---|
| noon | — | 72% |
| 1 p.m. | 73% | — |
By month
Each calendar month pooled over 2023–2026. Best: September (79%). Worst: July (67%).
By day of week
| Day | Flights | On time | Cancelled |
|---|---|---|---|
| Monday | 70 | — | — |
| Tuesday | 67 | — | — |
| Wednesday | 65 | — | — |
| Thursday | 67 | — | — |
| Friday | 71 | — | — |
| Saturday | 67 | — | — |
| Sunday | 66 | — | — |
Why flights were late
Share of delay minutes on flights 15+ minutes late, as reported to BTS by the airlines.
Cancellations: airline 2 · weather 2
Month by month
Not enough months with data to draw a trend.
Worst days in the past year
| Date | Flights | On time | Cancelled |
|---|---|---|---|
| Sep 13, 2025 | 3 | 0% | 1 |
| Sep 19, 2025 | 3 | 33% | 0 |
| Jul 17, 2026 | 3 | 33% | 0 |
| Sep 15, 2025 | 3 | 33% | 0 |
| Sep 14, 2025 | 3 | 33% | 0 |
Questions
How often are flights from MSO to ORD on time?
74% of 473 scheduled flights from Missoula, MT to Chicago, IL arrived within 15 minutes of schedule between September 2025 and August 2026. 0.9% were cancelled.
What is the best time of day to fly MSO to ORD?
Flights scheduled to leave at 1 p.m. were the most reliable (73% on time). The noon departures were the least (72%).
Which airline is most on time from MSO to ORD?
American Airlines: 74% of its 316 flights on the route arrived on time. United Airlines: 73%.
What month has the most delays from MSO to ORD?
July (67% on time). The best month is September (79%), over 2023–2026.
Related
- ORD → MSO (return)
- Missoula Montana (MSO) delays by hour
- Flights into Chicago O'Hare (ORD)
- American Airlines on-time record
- United Airlines on-time record
- Connecting off this flight? Check the risk
Domestic flights by the airlines that report to the U.S. DOT, plus their regional partners. "On time" means arriving less than 15 minutes after schedule; cancelled and diverted flights count as not on time. Past performance is a guide, not a forecast. Method.