Route reliability record
BZN→ORD
Bozeman to Chicago
- Flights
- 1,251
- Period
- September 2025 to August 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 77.3%. The late ones land an hour and a half behind schedule. That rests on 1,251 BZN to ORD flights, of which United Airlines flew 720 at 77.6% on time.
Best time to fly BZN to ORD: a 5am–8am departure, ideally on a Tuesday. Flights in that window arrived on time 86.6% of the time and Tuesday flights 81.3%, against 73.2% for the route overall.
The national on-time rate over the same period is 77.3%, 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
73.2%
Arrivals under 15 minutes late, of 1,233 completed flights
Avg delay
88 min
Across delayed arrivals only, not all flights
Cancelled
0.88%
National rate is 1.89%
Best carrier
United
77.6% on time across 720 flights
These figures cover 1,251 flights between September 2025 and August 2026. Beyond the headline rate, 11.7% 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 BZN to ORD
The choice of carrier is not cosmetic here. United Airlines arrives on time 77.6% of the time; American Airlines manages 66.4%. Sample sizes sit next to every figure, because a two-point gap across 444 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 720 | 77.6% | 91 min | 0.97% | B+ |
| Envoy Airthin sample | 41 | 75.6% | 71 min | 0.00% | B+ |
| SkyWest Airlinesthin sample | 46 | 69.6% | 53 min | 0.00% | C+ |
| American Airlines | 444 | 66.4% | 89 min | 0.90% | C+ |
United leads American by 11 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
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.
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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 | 76.8% | 77.6% | 0.97% | 8am–11am, Tue | UA 2202 12:48 |
| 2. BZN → ORDBozeman to Chicago | American Airlines | 65.8% | 66.4% | 0.90% | 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 23 points, against 11 points between the best and worst carrier.
- 5am–8am83 flights86.6%
- 8am–11am261 flights85.1%
- 11am–2pm654 flights69.5%
- 2pm–5pm154 flights63.4%
- 5pm–8pm99 flights71.4%
- 8pm–5am—
Scale runs 55% to 90%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 86.6% of the time, against 63.4% for the afternoon window. That is 23 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 11am–2pm window is the busiest, with 654 flights scheduled in it.
Explore
Filter BZN to ORD 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 BZN to ORD, the best departure window is 5am–8am at 86.6% on time and the worst is 2pm–5pm at 63.4%, a wide gap of 23.2 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am86.6%
- 8–11am85.1%
- 11am–2pm69.5%
- 2–5pm63.4%
- 5–8pm71.4%
- 8pm–5am—
best all US flightsScale 55% to 95%. Cells under 30 flights show a dash.
Across the year
When delays peak on this route
This route's year swings by 21 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 65.8% on time, 21 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. July was the busiest month here, with 154 flights.
Across the week, Tuesday is the strongest day at 81.3% on time and Sunday the weakest at 68.3%, a spread of 13 points.
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.
- 39%National Airspace System
- 37%Late-arriving aircraft
- 21%Carrier
- 3%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. Across 29,000 reported delay minutes here, that single category outweighs weather by 11 to one. The split is drawn from 29,042 reported delay minutes.
39% of delay minutes are charged to the National Airspace System: air traffic volume, runway configuration, ground stops. No carrier can price its way out of that, which is why airport choice moves the number here more than carrier choice does. That is 11,000 minutes out of 29,000, against a national NAS share of 21%.
Cancellations are rare at 0.88%, 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
11.7% 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 68.2% on time across 1,252 flights, 5 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 5 points of difference.
The sample behind these figures is 1,251 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 65.8%, a swing of 21 points. If the dates move at all, move them out of July before you think about anything else. 1,233 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 26.8% of the 1,251 flights in this analysis, against 22.7% 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 77.6% on time across 720 flights. American Airlines is at the other end on 66.4%, a gap of 11 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 86.6% on time. The 2pm–5pm window is the weakest at 63.4%, 23 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 65.8% on time, compared with 87.2% in May. Across the year that is 21 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 ORD77.6%
- American Airlines on BZN to ORD66.4%
- BZN to DEN, a related route77.5%
- LGA to ORD, a related route66.7%
- BZN to SEA, a related route84.1%
- United Airlines on-time record77.6%
- Envoy Air on-time record75.6%
- SkyWest Airlines on-time record69.6%
- Flying to ski country: which routes into the mountains run on time
- Why the first flight of the morning is statistically safest
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.
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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.