Carrier route record

AABOI→ORD

American Airlines · Boise to Chicago

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 BOI to ORD draws a D+. Roughly one flight in three arrives at least 15 minutes late, and the typical late arrival is close to two hours behind schedule. Build slack into anything you connect to. That rests on 208 flights, with a median arrival 1 minute early.

The national on-time rate over the same period is 77.3%, so American on BOI to ORD runs 14 points behind the country as a whole. Across a thousand flights that is about 138 extra late arrivals.

On time

63.5%

Arrivals under 15 minutes late, of 208 completed flights

Avg delay

102 min

Across delayed arrivals only, not all flights

Cancelled

0.00%

National rate is 1.89%

Whole route

74.9%

Every carrier on BOI to ORD, 1,111 flights

These figures cover 208 flights between September 2025 and August 2026. Beyond the headline rate, 14.9% of arrivals land a full hour or more behind schedule, against 8.3% nationally.

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Carrier by carrier

American against every carrier on BOI to ORD

American flew 208 of the 1,111 flights on BOI to ORD, about 19% of it. Its 63.5% on time is 11 points worse than the route as a whole, which runs 74.9%. Ranked by on-time rate it is last of four carriers on the route, where the range runs from SkyWest at 82.9% to American at 63.5%. 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.

On-time performance by carrier on BOI to ORD
Airline	Flights	On time	Avg delay	Cancelled	Grade
SkyWest Airlines	507	82.9%	78 min	2.17%	B
United Airlinesthin sample	244	75.5%	91 min	0.82%	B+
Envoy Airthin sample	152	63.8%	111 min	0.00%	D+
American Airlines (this page)thin sample	208	63.5%	102 min	0.00%	D+

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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–11am—
11am–2pm105 flights62.9%
2pm–5pm103 flights64.1%
5pm–8pm—
8pm–5am—

Scale runs 55% to 70%. Rows with fewer than 30 flights show a dash.

The 2pm–5pm window is the strongest at 64.1% on time. The full set of windows spans about a point.

Across the year

American on BOI to ORD through the year

Jul–Sep 202530 flights56.7%
Oct–Dec 202531 flights71.0%
Apr–Jun 202685 flights63.5%
Jul–Sep 202662 flights62.9%

Scale runs 50% to 75%.

Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 63.5% on time across 208 flights.

American on BOI to ORD did not run the same all year. Its best quarter was Oct–Dec 2025 at 71.0% on time and its weakest Jul–Sep 2025 at 56.7%, a swing of 14 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, Tuesday is the strongest day at 73.3% on time and Monday the weakest at 53.3%, a spread of 20 points.

Arrival by arrival

How late American on BOI to ORD runs when it is late

American on BOI to ORD often beats the schedule: 58 of 208 completed flights, 28%, arrived 15 minutes or more early. The 76 late arrivals split 23 under half an hour, 22 between 30 and 60 minutes, and 31 an hour or more.

15+ min early58 flights27.9%
Within 15 min74 flights35.6%
15–29 min late23 flights11.1%
30–59 min late22 flights10.6%
1–2 hours late16 flights7.7%
2+ hours late15 flights7.2%

Scale runs 0% to 100%.

Share of 208 completed flights by arrival against schedule.

16 of 73 late departures made up the time and arrived on time, 22% of them. In the other direction, 19 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at ORD.

The worst days

Worst days for American on BOI to ORD

The latest arrival of the period was on 28 October 2025, 19 hours 23 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The five worst days are spread across October, August, June and July, with no single month standing out.

The latest arrivals of American on BOI to ORD in the period
Date	Arrived late by	Largest filed cause
28 October 2025	19 hours 23 minutes	Carrier
24 August 2026	17 hours 9 minutes	Carrier
10 June 2026	6 hours 56 minutes	Extreme weather
4 July 2026	5 hours 23 minutes	National Airspace System
22 October 2025	4 hours 45 minutes	Late-arriving aircraft

Delay causes

Why American runs late on this route

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 7,771 reported delay minutes.

Carrier
39%
Late-arriving aircraft
29%
National Airspace System
19%
Extreme weather
14%

Extreme weather accounts for 14% of delay minutes, well above the single-digit share typical across the system. Weather delays are lumpy: they arrive as whole bad days rather than as a steady drag, so the monthly strip above is the more useful view of the risk. The national share is 6%, so this operation carries roughly 2.3 times the usual weather exposure. The split is drawn from 7,771 reported delay minutes.

The largest share of delay minutes, 39%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 3,024 of the 7,771 delay minutes reported 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

14.9% 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 1,437 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 78.4% on time across 208 flights, 15 points above 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 BOI to ORD

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 63.5% 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.

Where to go next

Source: US DOT Bureau of Transportation Statistics, on-time performance data, September 2025 to August 2026. Last updated 22 October 2026; recomputed monthly. How this data is collected.

Key figures