Route reliability record
BZN→ORD
Bozeman to Chicago
- Flights
- 1,255
- Period
- July 2025 to June 2026
- Distance
- 1,185 mi
- Carriers
- 4
This route sits in the middle of the pack with a C. Close to three flights in four arrive on time by the DOT's definition, 4 points worse than the national rate of 77.6%. The late ones land an hour and a half behind schedule. That rests on 1,255 BZN to ORD flights, of which United Airlines flew 658 at 79.7% on time.
Best time to fly BZN to ORD: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 89.0% of the time and Tuesday flights 76.9%, against 73.5% for the route overall.
The national on-time rate over the same period is 77.6%, so this route runs 4 points behind the country as a whole. Across a thousand flights that is about 41 extra late arrivals.
Key figures
On time
73.5%
Arrivals under 15 minutes late, of 1,235 completed flights
Avg delay
90 min
Across delayed arrivals only, not all flights
Cancelled
1.04%
National rate is 1.81%
Best carrier
United
79.7% on time across 658 flights
These figures cover 1,255 flights between July 2025 and June 2026. Beyond the headline rate, 10.8% 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 BZN to ORD
The choice of carrier is not cosmetic here. United Airlines arrives on time 79.7% of the time; American Airlines manages 65.2%. Sample sizes sit next to every figure, because a two-point gap across 467 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 658 | 79.7% | 79 min | 1.52% | B |
| Envoy Airthin sample | 41 | 75.6% | 71 min | 0.00% | B+ |
| SkyWest Airlinesthin sample | 89 | 70.8% | 57 min | 0.00% | C+ |
| American Airlines | 467 | 65.2% | 105 min | 0.64% | C+ |
The spread between United and American is 15 points, wide enough that it should decide the booking. On a hundred trips that is 15 more arrivals inside the on-time window.
Flight by flight
Flights on BZN to ORD
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 Bozeman to Chicago
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. BZN → ORDBozeman to Chicago | United Airlines | 78.5% | 79.7% | 1.52% | 5am–8am, Thu | UA 2202 12:48 |
| 2. BZN → ORDBozeman to Chicago | American Airlines | 64.8% | 65.2% | 0.64% | 5am–8am, 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 21 points, against 15 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am132 flights89.0%
- 8am–11am255 flights82.9%
- 11am–2pm654 flights68.0%
- 2pm–5pm134 flights68.4%
- 5pm–8pm80 flights72.5%
- 8pm–5am—
Scale runs 60% to 95%. Rows with fewer than 30 flights show a dash.
The weak window here is the middle of the day, not the evening: 11am–2pm runs 68.0% on time against 89.0% for 5am–8am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise. The 11am–2pm window is the busiest, with 654 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 22 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.
July is the worst month at 65.5% on time, 22 points below May, the best at 87.2%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. June was the busiest month here, with 150 flights.
Across the week, Tuesday is the strongest day at 76.9% on time and Sunday the weakest at 66.5%. 10 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 29,000 reported delay minutes.
- 37%Late-arriving aircraft
- 32%National Airspace System
- 26%Carrier
- 6%Extreme weather
- 0%Security
37% 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 29,000 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 29,345 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 89.0% on time here.
Cancellations sit at 1.04% against a national 1.81%, which is ordinary. Diversions add another 0.56%.
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. 10.8% 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 67.4% on time across 1,256 flights, 6 points below 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 1,255 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 ORD 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. May runs 87.2% on time and July 65.5%, a swing of 22 points. If the dates move at all, move them out of July before you think about anything else. 1,235 completed flights over 12 months sit behind that.
Common questions
BZN to ORD questions
How often is BZN to ORD delayed?
About one flight in four arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 26.5% of the 1,255 flights in this analysis, against 22.4% nationally. Delayed flights are late by an hour and a half on average.
Which airline is most reliable on BZN to ORD?
United Airlines leads at 79.7% on time across 658 flights. American Airlines is at the other end on 65.2%, a gap of 15 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 BZN to ORD?
The 5am–8am departure window is the strongest at 89.0% on time. The 11am–2pm window is the weakest at 68.0%, 21 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 July delays on BZN to ORD?
July is the weakest month at 65.5% on time, compared with 87.2% in May. Across the year that is 22 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
- ORD to BZN — the return legseparate record
- Chicago O'Hare International (ORD) delay statistics
- United Airlines on BZN to ORD79.7%
- American Airlines on BZN to ORD65.2%
- BZN to DEN, a related route76.9%
- LGA to ORD, a related route67.3%
- BZN to SEA, a related route84.4%
- United Airlines on-time record79.7%
- Envoy Air on-time record75.6%
- SkyWest Airlines on-time record70.8%
- Why the first flight of the morning is statistically safest
- Same route, different airline: where the carrier you pick matters most
Direction matters. BZN to ORD and ORD to BZN are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
Embed BZN to ORD’s on-time badge on your site
Paste this into a web page. The badge shows the current on-time rate, cancellation rate and grade, and updates every month. Preview it, or build a badge for another route or airport.
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.