Route reliability record
ORD→BZN
Chicago to Bozeman
- Flights
- 1,256
- Period
- July 2025 to June 2026
- Distance
- 1,185 mi
- Carriers
- 4
This route draws a C+. About one flight in three arrives at least 15 minutes late, and the typical late arrival is about an hour behind schedule. Build slack into anything you connect to. That rests on 1,256 ORD to BZN flights, of which United Airlines flew 658 at 69.6% on time.
Best time to fly ORD to BZN: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 79.7% of the time and Tuesday flights 72.6%, against 67.4% for the route overall.
The national on-time rate over the same period is 77.6%, so this route runs 10 points behind the country as a whole. Across a thousand flights that is about 102 extra late arrivals.
Key figures
On time
67.4%
Arrivals under 15 minutes late, of 1,241 completed flights
Avg delay
63 min
Across delayed arrivals only, not all flights
Cancelled
0.72%
National rate is 1.81%
Best carrier
United
69.6% on time across 658 flights
These figures cover 1,256 flights between July 2025 and June 2026. Beyond the headline rate, 11.4% 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
Which airline is most reliable on ORD to BZN
The two carriers here are closely matched: 6 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| SkyWest Airlinesthin sample | 89 | 75.0% | 63 min | 0.00% | B+ |
| United Airlines | 658 | 69.6% | 64 min | 1.06% | C |
| American Airlines | 468 | 64.0% | 64 min | 0.43% | D+ |
| Envoy Airthin sample | 41 | 55.0% | 31 min | 0.00% | D+ |
No carrier stands out. United tops the table at 69.6%, 6 points clear of the bottom, which is inside the range this kind of sample moves year to year.
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.
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 | 68.9% | 69.6% | 1.06% | 8am–11am, Mon | UA 224 09:15 |
| 2. ORD → BZNChicago to Bozeman | American Airlines | 63.7% | 64.0% | 0.43% | 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 32 points, against 6 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am60 flights79.7%
- 8am–11am656 flights71.2%
- 11am–2pm212 flights69.8%
- 2pm–5pm102 flights67.6%
- 5pm–8pm88 flights47.7%
- 8pm–5am138 flights52.7%
Scale runs 40% to 85%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 47.7% on time, against 79.7% for the 5am–8am 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.
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. June was the busiest month here, with 150 flights.
Across the week, Tuesday is the strongest day at 72.6% on time and Friday the weakest at 59.0%. 14 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Late-arriving aircraft accounts for 45% of the 25,000 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.
- 45%Late-arriving aircraft
- 25%Carrier
- 23%National Airspace System
- 6%Extreme weather
45% 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 25,000 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 25,278 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 79.7% on time here.
Cancellations are rare at 0.72%, 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 actually costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 11.4% 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 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. 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 73.5% on time across 1,255 flights, 6 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 6 points of difference.
The sample behind these figures is 1,256 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. 1,241 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 32.6% of the 1,256 flights in this analysis, against 22.4% nationally. Delayed flights are late by about an hour on average.
Which airline is most reliable on ORD to BZN?
United Airlines leads at 69.6% on time across 658 flights. American Airlines is at the other end on 64.0%, a gap of 6 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 5am–8am departure window is the strongest at 79.7% on time. The 5pm–8pm window is the weakest at 47.7%, 32 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 BZN69.6%
- American Airlines on ORD to BZN64.0%
- ORD to LGA, a related route67.3%
- DEN to BZN, a related route78.1%
- ORD to BOS, a related route67.6%
- SkyWest Airlines on-time record75.0%
- United Airlines on-time record69.6%
- American Airlines on-time record64.0%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.04 million flight records
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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.