Route reliability record
LAX→ORD
Los Angeles to Chicago
- Flights
- 6,981
- Period
- June 2025 to May 2026
- Distance
- 1,744 mi
- Carriers
- 4
This route lands a B, level with the national rate of 77.4%. Roughly one flight in four arrive 15 minutes late or worse, and those flights are late by an hour and a half on average. That is a workable record, not a spotless one. That rests on 6,981 flights, of which United Airlines flew 3,394 at 80.9% on time.
The US average over the same twelve months is 77.4%, so there is little to separate this route from the country as a whole. The variation that matters here is internal: which carrier, and what time of day.
Key figures
On time
76.9%
Arrivals under 15 minutes late, of 6,820 completed flights
Avg delay
84 min
Across delayed arrivals only, not all flights
Cancelled
1.66%
National rate is 1.80%
Best carrier
United
80.9% on time across 3,394 flights
These figures cover 6,981 flights between June 2025 and May 2026. Beyond the headline rate, 8.8% 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 LAX to ORD
The choice of carrier is not cosmetic here. United Airlines arrives on time 80.9% of the time; American Airlines manages 73.2%. Sample sizes sit next to every figure, because a two-point gap across 3,039 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Spirit Airlinesthin sample | 300 | 81.9% | 74 min | 3.67% | B− |
| United Airlines | 3,394 | 80.9% | 64 min | 0.74% | B+ |
| American Airlines | 3,039 | 73.2% | 94 min | 2.27% | C |
| Frontier Airlinesthin sample | 248 | 60.6% | 146 min | 4.44% | D− |
United leads American by 8 points. Real, but small enough that a better departure time on the weaker carrier can outweigh 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 25 points, against 8 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am1,102 flights91.9%
- 8am–11am1,398 flights77.5%
- 11am–2pm1,094 flights66.9%
- 2pm–5pm974 flights68.0%
- 5pm–8pm798 flights75.5%
- 8pm–5am1,615 flights78.8%
Scale runs 60% to 95%. 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 66.9% on time against 91.9% for 5am–8am. That shape usually means a departure bank rather than an accumulating delay, so the recovery later in the afternoon is real rather than noise.
Across the year
When delays peak on this route
This route's year swings by 14 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.
Delays peak in March, when the on-time rate falls to 69.4%. February is the strongest month at 83.4%. Moving a flexible trip across that boundary buys 14 points.
Across the week, Tuesday is the strongest day at 80.6% on time and Sunday the weakest at 73.9%. 7 points is a smaller lever than departure hour, but it is free.
Delay causes
Why this route gets delayed
One category carries most of the weight here. Late-arriving aircraft accounts for 43% of the 132,000 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.
- 43%Late-arriving aircraft
- 31%Carrier
- 24%National Airspace System
- 2%Extreme weather
- 0%Security
43% 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 132,000 reported delay minutes here, that single category outweighs weather by 25 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 practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 91.9% on time here.
Cancellations sit at 1.66% against a national 1.80%, which is ordinary. Diversions add another 0.64%.
Connections and stage length
What a delay here actually costs
8.8% of arrivals land an hour or more late, close to the national 8.2%. 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 are the an hour and a half kind, which a normal layover absorbs.
At 1,744 miles this is transcontinental flying, and long routes get a quiet structural advantage. Scheduled block time on a flight this length carries more padding in absolute minutes, so a twenty-minute late departure often still becomes an on-time arrival. Read the on-time rate here as slightly flattering next to a short-haul route with the same operational quality.
The return leg is a different operation and performs like one: it runs 73.6% on time across 6,981 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 6,981 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 calendar is the biggest lever here, not the carrier or the hour. February runs 83.4% on time and March 69.4%, a swing of 14 points. If the dates move at all, move them out of March before you think about anything else.
Common questions
LAX to ORD questions
How often is LAX to ORD delayed?
Roughly 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 23.1% of the 6,981 flights in this analysis, against 22.6% nationally. Delayed flights are late by an hour and a half on average.
Which airline is most reliable on LAX to ORD?
United Airlines leads at 80.9% on time across 3,394 flights. American Airlines is at the other end on 73.2%, a gap of 8 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 LAX to ORD?
The 5am–8am departure window is the strongest at 91.9% on time. The 11am–2pm window is the weakest at 66.9%, 25 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 March delays on LAX to ORD?
March is the weakest month at 69.4% on time, compared with 83.4% in February. Across the year that is 14 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 LAX — the return legseparate record
- Los Angeles International (LAX) delay statistics
- Chicago O'Hare International (ORD) delay statistics
- Spirit Airlines on-time record81.9%
- United Airlines on-time record80.9%
- American Airlines on-time record73.2%
- Why the first flight of the morning is statistically safest
- The best time of day to fly, according to 7.05 million flight records
Direction matters. LAX to ORD and ORD to LAX 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, June 2025 to May 2026. Updated monthly. How this data is collected.