Carrier route record
AAORD→BOI
American Airlines · Chicago to Boise
- Flights
- 172
- Period
- July 2025 to June 2026
- Share of route
- 16%
- Carriers
- 4
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with American Airlines.
American on ORD to BOI lands a B+, level with the national rate of 77.6%. Roughly one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That is a workable record, not a spotless one. That rests on 172 flights, with a median arrival 3 minutes early.
The US average over the same twelve months is 77.6%, 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
77.9%
Arrivals under 15 minutes late, of 172 completed flights
Avg delay
67 min
Across delayed arrivals only, not all flights
Cancelled
0.00%
National rate is 1.81%
Whole route
69.1%
Every carrier on ORD to BOI, 1,108 flights
These figures cover 172 flights between July 2025 and June 2026. Beyond the headline rate, 8.7% 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
American against every carrier on ORD to BOI
American flew 172 of the 1,108 flights on ORD to BOI, about 16% of it. Its 77.9% on time is 9 points better than the route as a whole, which runs 69.1%. Ranked by on-time rate it is number two of four carriers on the route, where the range runs from United at 78.2% to SkyWest at 62.6%. 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 |
|---|---|---|---|---|---|
| United Airlinesthin sample | 245 | 78.2% | 59 min | 0.41% | B+ |
| American Airlines (this page)thin sample | 172 | 77.9% | 67 min | 0.00% | B+ |
| Envoy Airthin sample | 188 | 66.3% | 49 min | 0.00% | C+ |
| SkyWest Airlines | 503 | 62.6% | 87 min | 2.58% | D |
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 172 flights.
- 5am–8am—
- 8am–11am131 flights77.9%
- 11am–2pm41 flights78.0%
- 2pm–5pm—
- 5pm–8pm—
- 8pm–5am—
Scale runs 70% to 85%. Rows with fewer than 30 flights show a dash.
The 11am–2pm window is the strongest at 78.0% on time. The full set of windows spans half a point.
Across the year
American on ORD to BOI through the year
- Jul–Sep 202556 flights73.2%
- Oct–Dec 202531 flights83.9%
- Apr–Jun 202685 flights78.8%
Scale runs 65% to 90%. Rows with fewer than 30 flights show a dash.
Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 77.9% on time across 172 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 2025 at 73.2%, a swing of 11 points on roughly 57 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.
Delay causes
Why American runs late on this route
One category carries most of the weight here. Late-arriving aircraft accounts for 52% of the 2,551 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.
- 52%Late-arriving aircraft
- 37%Carrier
- 9%National Airspace System
- 1%Extreme weather
52% 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 2,551 reported delay minutes here, that single category outweighs weather by 42 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 2,551 reported delay minutes.
The largest share of delay minutes, 37%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. Unlike weather, that is a management outcome, and it is the category where the gap between two carriers on the same schedule is genuinely earned. It accounts for 945 of the 2,551 delay minutes reported here.
Cancellations are rare at 0.00%, below the national 1.81% 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
8.7% of arrivals land an hour or more late, close to the national 8.1%. That is the figure that decides a connection, and it says 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. 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 61.4% on time across 172 flights, 17 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 17 points of difference.
One caution: this is a thin sample. 172 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. 172 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 77.9% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 172 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 BOI78.2%
- Envoy Air on ORD to BOI66.3%
- SkyWest Airlines on ORD to BOI62.6%
- 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, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.