Route reliability record
BUF→ORD
Buffalo to Chicago
- Flights
- 2,196
- Period
- July 2025 to June 2026
- Distance
- 474 mi
- Carriers
- 5
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 2,196 flights, of which American Airlines flew 476 at 84.0% on time.
American Airlines is the most reliable of the three carriers covered here at 84.0% on time across 476 flights.
Key figures
On time
74.0%
Arrivals under 15 minutes late, of 2,130 completed flights
Avg delay
100 min
Across delayed arrivals only, not all flights
Cancelled
2.87%
National rate is 1.81%
Best carrier
American
84.0% on time across 476 flights
These figures cover 2,196 flights between July 2025 and June 2026. Beyond the headline rate, 11.1% 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 BUF to ORD
The choice of carrier is not cosmetic here. American Airlines arrives on time 84.0% of the time; Envoy Air manages 70.8%. Sample sizes sit next to every figure, because a two-point gap across 423 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| American Airlines | 476 | 84.0% | 124 min | 1.47% | B |
| Republic Airwaysthin sample | 355 | 76.2% | 95 min | 3.66% | B− |
| United Airlines | 612 | 74.1% | 88 min | 1.47% | C |
| Envoy Air | 423 | 70.8% | 68 min | 3.31% | C− |
| SkyWest Airlinesthin sample | 330 | 60.2% | 134 min | 6.06% | D− |
Envoy Air cancels 3.3% of what it schedules here, the highest in the table. A cancelled flight never appears in an on-time rate, so read that column alongside the punctuality one rather than after it.
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 31 points, against 13 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am679 flights83.7%
- 8am–11am338 flights84.5%
- 11am–2pm380 flights84.0%
- 2pm–5pm180 flights64.1%
- 5pm–8pm616 flights53.7%
- 8pm–5am3 flights—
Scale runs 45% to 90%. Rows with fewer than 30 flights show a dash.
The 5pm–8pm window is where this operation falls apart: 53.7% on time, against 84.5% 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 5am–8am window is the busiest, with 679 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 19 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.
January is the weak month at 64.5% on time, against 83.1% in June. Winter delays cluster: a single storm system can account for most of a month's shortfall, so an average December hides both very good weeks and genuinely unflyable days. May was the busiest month here, with 216 flights.
Across the week, Thursday is the strongest day at 78.1% on time and Sunday the weakest at 72.1%. 6 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 55,000 reported delay minutes.
- 33%Late-arriving aircraft
- 32%Carrier
- 29%National Airspace System
- 5%Extreme weather
- 0%Security
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 84.5% on time here. The split is drawn from 55,356 reported delay minutes.
No single cause dominates. late-arriving aircraft at 33%, carrier at 32% and national airspace system at 29% split the 55,000 reported delay minutes between them. An even spread like this usually means the operation is running close to its designed capacity with no one obvious weak point, and it is the hardest pattern for a traveller to route around.
Cancellations run at 2.87%, against 1.81% nationally. That is roughly one flight in 30 cancelled outright. A cancelled flight is invisible in every on-time figure on this page, so the punctuality numbers above describe only the flights that actually operated.
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. 11.1% 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.
At 474 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 8am–11am window matters as much as it does.
The return leg is a different operation and performs like one: it runs 70.6% on time across 2,195 flights, 3 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 3 points of difference.
The sample behind these figures is 2,196 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.
What to do with this
Booking this route
Put together: the delay figures matter less here than the 2.87% cancellation rate. A late arrival costs you an hour and a half; a cancelled flight costs you the day. Book the 8am–11am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 2,130 completed flights over 12 months sit behind that.
Common questions
BUF to ORD questions
How often is BUF to ORD delayed?
About one flight in four arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 26.0% of the 2,196 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 BUF to ORD?
American Airlines leads at 84.0% on time across 476 flights. Envoy Air is at the other end on 70.8%, a gap of 13 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 BUF to ORD?
The 8am–11am departure window is the strongest at 84.5% on time. The 5pm–8pm window is the weakest at 53.7%, 31 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 January delays on BUF to ORD?
January is the weakest month at 64.5% on time, compared with 83.1% in June. Across the year that is 19 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 BUF — the return legseparate record
- Chicago O'Hare International (ORD) delay statistics
- American Airlines on-time record84.0%
- Republic Airways on-time record76.2%
- United Airlines on-time record74.1%
- Why the first flight of the morning is statistically safest
- What a cancellation rate actually tells you (and what it hides)
Direction matters. BUF to ORD and ORD to BUF are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Updated monthly. How this data is collected.