Route reliability record
ORD→BZN
Chicago to Bozeman
- Flights
- 1,252
- Period
- September 2025 to August 2026
- Distance
- 1,185 mi
- Carriers
- 4
This route sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 9 points worse than the national rate of 77.3%. The late ones land about an hour behind schedule. That rests on 1,252 ORD to BZN flights, of which United Airlines flew 720 at 71.6% on time.
Best time to fly ORD to BZN: a 8am–11am departure, ideally on a Tuesday. Flights in that window arrived on time 73.3% of the time and Tuesday flights 76.9%, against 68.2% for the route overall.
The national on-time rate over the same period is 77.3%, so this route runs 9 points behind the country as a whole. Across a thousand flights that is about 91 extra late arrivals.
Key figures
On time
68.2%
Arrivals under 15 minutes late, of 1,239 completed flights
Avg delay
66 min
Across delayed arrivals only, not all flights
Cancelled
0.56%
National rate is 1.89%
Best carrier
United
71.6% on time across 720 flights
These figures cover 1,252 flights between September 2025 and August 2026. Beyond the headline rate, 11.6% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Carrier by carrier
Which airline is most reliable on ORD to BZN
The choice of carrier is not cosmetic here. United Airlines arrives on time 71.6% of the time; American Airlines manages 63.9%. Sample sizes sit next to every figure, because a two-point gap across 445 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 720 | 71.6% | 70 min | 0.56% | C+ |
| SkyWest Airlinesthin sample | 46 | 68.9% | 70 min | 0.00% | C+ |
| American Airlines | 445 | 63.9% | 64 min | 0.67% | D+ |
| Envoy Airthin sample | 41 | 55.0% | 31 min | 0.00% | D+ |
United leads American by 8 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Flight by flight
Flights on ORD to BZN
The flight numbers below flew this route at least 250 times in the period, busiest first. Each has its own record, with its schedule and delay causes.
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Best ways to make this trip
The most reliable ways to fly Chicago to Bozeman
Every airline on this route, ranked by how often a scheduled flight actually operated and arrived on time, with its best departure time and most punctual flight number. No nearby airport pair beat these.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. ORD → BZNChicago to Bozeman | United Airlines | 71.2% | 71.6% | 0.56% | 8am–11am, Tue | UA 224 09:10 |
| 2. ORD → BZNChicago to Bozeman | American Airlines | 63.5% | 63.9% | 0.67% | 11am–2pm, Tue | — |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
Departure window
The best time of day to leave
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 26 points, against 8 points between the best and worst carrier.
- 5am–8am17 flights—
- 8am–11am656 flights73.3%
- 11am–2pm251 flights69.1%
- 2pm–5pm110 flights64.5%
- 5pm–8pm88 flights47.7%
- 8pm–5am130 flights56.8%
Scale runs 40% to 80%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 47.7% on time, against 73.3% 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 8am–11am window is the busiest, with 656 flights scheduled in it.
Explore
Filter ORD to BZN by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On ORD to BZN, the best departure window is 8am–11am at 73.3% on time and the worst is 5pm–8pm at 47.7%, a wide gap of 25.6 points. All US flights leaving 8am–11am ran 83.9%.
- 5–8am—
- 8–11am73.3%
- 11am–2pm69.1%
- 2–5pm64.5%
- 5–8pm47.7%
- 8pm–5am56.8%
best all US flightsScale 40% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 36 points from best month to worst, which is wide. An annual average tells you very little about the week you are actually flying, so read the strip rather than the headline if your dates are fixed.
November is the best month on the calendar at 86.7% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. July was the busiest month here, with 154 flights.
Across the week, Tuesday is the strongest day at 76.9% on time and Friday the weakest at 60.8%, a spread of 16 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 45% of the 26,000 delay minutes carriers reported here, and the remaining four split what is left.
- 45%Late-arriving aircraft
- 26%National Airspace System
- 22%Carrier
- 6%Extreme weather
45% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 26,000 reported delay minutes here, that single category outweighs weather by 7 to one. The split is drawn from 25,814 reported delay minutes.
The practical consequence: the 8am–11am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 73.3% on time here.
Cancellations are rare at 0.56%, below the national 1.89% 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 actually costs
11.6% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
The 1,185 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.
The return leg is a different operation and performs like one: it runs 73.2% on time across 1,251 flights, 5 points above 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 5 points of difference.
The sample behind these figures is 1,252 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.
Work out the risk of missing a connection in BZN after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. November runs 86.7% on time and March 50.9%, a swing of 36 points. If the dates move at all, move them out of March before you think about anything else. 1,239 completed flights over 12 months sit behind that.
Common questions
ORD to BZN questions
How often is ORD to BZN delayed?
About one flight in three arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 31.8% of the 1,252 flights in this analysis, against 22.7% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on ORD to BZN?
United Airlines leads at 71.6% on time across 720 flights. American Airlines is at the other end on 63.9%, a gap of 8 points. Sample size matters as much as the percentage: a rate built from a few hundred flights moves around far more than one built from ten thousand.
What time of day has the fewest delays on ORD to BZN?
The 8am–11am departure window is the strongest at 73.3% on time. The 5pm–8pm window is the weakest at 47.7%, 26 points behind. Later departures inherit delays from earlier flights the same aircraft has already flown, which is why the curve slopes the way it does.
How bad are March delays on ORD to BZN?
March is the weakest month at 50.9% on time, compared with 86.7% in November. Across the year that is 36 points between the best and worst months. Moving flexible dates out of that month is one of the few things that reliably helps.
Related
Where to go next
- BZN to ORD — the return legseparate record
- Chicago O'Hare International (ORD) delay statistics
- United Airlines on ORD to BZN71.6%
- American Airlines on ORD to BZN63.9%
- ORD to LGA, a related route66.6%
- DEN to BZN, a related route78.1%
- ORD to BOS, a related route66.6%
- United Airlines on-time record71.6%
- SkyWest Airlines on-time record68.9%
- American Airlines on-time record63.9%
- Flying to ski country: which routes into the mountains run on time
- Why the first flight of the morning is statistically safest
Direction matters. ORD to BZN and BZN to ORD are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.