Carrier route record
AAORD→BOI
American Airlines · Chicago to Boise
- Flights
- 208
- Period
- September 2025 to August 2026
- Share of route
- 19%
- Carriers
- 4
Historical statistics for September 2025 to August 2026, not live status. For today’s flights, check with American Airlines.
American on ORD to BOI lands a B+, about a point better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 208 flights, with a median arrival 3 minutes early.
The US average over the same twelve months is 77.3%, so there is little to separate American on ORD to BOI from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
78.4%
Arrivals under 15 minutes late, of 208 completed flights
Avg delay
62 min
Across delayed arrivals only, not all flights
Cancelled
0.00%
National rate is 1.89%
Whole route
69.3%
Every carrier on ORD to BOI, 1,108 flights
These figures cover 208 flights between September 2025 and August 2026. Beyond the headline rate, 8.2% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
Fare search by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Carrier by carrier
American against every carrier on ORD to BOI
American flew 208 of the 1,108 flights on ORD to BOI, about 19% of it. Its 78.4% on time is 9 points better than the route as a whole, which runs 69.3%. Ranked by on-time rate it is first of four carriers on the route, where the range runs from American at 78.4% to Envoy at 62.9%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.
Only one carrier clears this site's 365-flight floor here, so there is no comparison to draw. The table below is the full picture.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| American Airlines (this page)thin sample | 208 | 78.4% | 62 min | 0.00% | B+ |
| United Airlinesthin sample | 245 | 77.4% | 58 min | 0.41% | B+ |
| SkyWest Airlines | 503 | 63.4% | 82 min | 3.18% | D− |
| Envoy Airthin sample | 152 | 62.9% | 51 min | 0.00% | D+ |
Timetable by Aviasales, a Travelpayouts partner. Booking through it may earn this site a commission at no cost to you; it changes no figure here.
Departure window
When American runs best on this route
Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 208 flights.
- 5am–8am—
- 8am–11am105 flights81.9%
- 11am–2pm103 flights74.8%
- 2pm–5pm—
- 5pm–8pm—
- 8pm–5am—
Scale runs 65% to 85%. 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 74.8% on time against 81.9% for 8am–11am. 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 8am–11am window is the busiest, with 105 flights scheduled in it.
Across the year
American on ORD to BOI through the year
- Jul–Sep 202530 flights83.3%
- Oct–Dec 202531 flights83.9%
- Apr–Jun 202685 flights78.8%
- Jul–Sep 202662 flights72.6%
Scale runs 65% to 90%.
Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 78.4% on time across 208 flights.
American on ORD to BOI did not run the same all year. Its best quarter was Oct–Dec 2025 at 83.9% on time and its weakest Jul–Sep 2026 at 72.6%, a swing of 11 points on roughly 52 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
Across the week, Wednesday is the strongest day at 83.3% on time and Monday the weakest at 73.3%, a spread of 10 points.
Arrival by arrival
How late American on ORD to BOI runs when it is late
The 45 late arrivals split 15 under half an hour, 13 between 30 and 60 minutes, and 17 an hour or more.
- 15+ min early50 flights24.0%
- Within 15 min113 flights54.3%
- 15–29 min late15 flights7.2%
- 30–59 min late13 flights6.3%
- 1–2 hours late13 flights6.3%
- 2+ hours late4 flights1.9%
Scale runs 0% to 100%.
Share of 208 completed flights by arrival against schedule.
8 of 44 late departures made up the time and arrived on time, 18% of them. 9 flights left on time and still arrived late.
The worst days
Worst days for American on ORD to BOI
The latest arrival of the period was on 22 October 2025, 5 hours 16 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. The same cause led on four of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 22 October 2025 | 5 hours 16 minutes | Late-arriving aircraft |
| 7 June 2026 | 4 hours 14 minutes | Carrier |
| 15 October 2025 | 3 hours 4 minutes | Late-arriving aircraft |
| 13 September 2025 | 2 hours 38 minutes | Late-arriving aircraft |
| 18 May 2026 | 1 hour 53 minutes | Late-arriving aircraft |
Delay causes
Why American runs late on this route
Late-arriving aircraft accounts for 55% of the 2,787 delay minutes carriers reported here, and the remaining four split what is left.
- 55%Late-arriving aircraft
- 28%Carrier
- 15%National Airspace System
- 2%Extreme weather
55% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 2,787 reported delay minutes here, that single category outweighs weather by 33 to one. The split is drawn from 2,787 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 81.9% on time here.
Cancellations are rare at 0.00%, below the national 1.89% and low enough to earn the plus on the grade. Almost no flights are called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here costs
8.2% of arrivals land an hour or more late, close to the national 8.3%, so a 60 to 75 minute layover is reasonable here while anything under 45 minutes is a bet. Most delays on this route last about an hour, which a normal layover absorbs.
The 1,437 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 63.5% on time across 208 flights, 15 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 15 points of difference.
One caution: this is a thin sample. 208 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking American on ORD to BOI
Put together: treat all of this as provisional. 208 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 78.4% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 208 completed flights over 12 months sit behind that.
Related
Where to go next
- ORD to BOI, every carrier
- American on BOI to ORD, the return leg
- United Airlines on ORD to BOI77.4%
- SkyWest Airlines on ORD to BOI63.4%
- Envoy Air on ORD to BOI62.9%
- American Airlines network-wide record
- Chicago O'Hare International (ORD) delay statistics
- Why the first flight of the morning is statistically safest
- Connecting flights: how much buffer the data says you need
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.