Route reliability record
ONT→DFW
Ontario to Dallas-Fort Worth
- Flights
- 2,307
- Period
- July 2025 to June 2026
- Distance
- 1,188 mi
- Carriers
- 2
This route lands a B−, level with the national rate of 77.6%. Roughly one flight in five 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 2,307 flights, with a median arrival 8 minutes early.
The US average over the same twelve months is 77.6%, 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
78.2%
Arrivals under 15 minutes late, of 2,218 completed flights
Avg delay
94 min
Across delayed arrivals only, not all flights
Cancelled
3.03%
National rate is 1.81%
Best carrier
American
78.6% on time across 1,985 flights
These figures cover 2,307 flights between July 2025 and June 2026. Beyond the headline rate, 8.3% 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 ONT to DFW
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 | 1,985 | 78.6% | 98 min | 2.97% | B |
| Frontier Airlinesthin sample | 322 | 75.6% | 68 min | 3.42% | B− |
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 22 points, against half a point between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am617 flights89.1%
- 8am–11am367 flights77.6%
- 11am–2pm485 flights71.9%
- 2pm–5pm422 flights69.2%
- 5pm–8pm73 flights67.1%
- 8pm–5am343 flights81.4%
Scale runs 60% to 95%. Rows with fewer than 30 flights show a dash.
Book the early departure. Flights leaving between 5am–8am arrive on time 89.1% of the time, against 67.1% for the evening window. That is 22 points of difference for no extra money, and it comes from the same aircraft having had no earlier flight to fall behind on. The 5am–8am window is the busiest, with 617 flights scheduled in it.
Across the year
When delays peak on this route
This route's year swings by 23 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.
July is the worst month at 65.7% on time, 23 points below April, the best at 88.2%. Summer afternoon convection and peak-season schedules land on the same weeks every year, so this is a pattern you can book around rather than a run of bad luck. July was the busiest month here, with 224 flights.
Across the week, Tuesday is the strongest day at 81.4% on time and Saturday the weakest at 75.6%. 6 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 44% of the 45,000 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.
- 44%Late-arriving aircraft
- 41%Carrier
- 12%National Airspace System
- 3%Extreme weather
- 0%Security
44% 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 45,000 reported delay minutes here, that single category outweighs weather by 13 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 45,255 reported delay minutes.
The largest share of delay minutes, 41%, 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 19,000 of the 45,000 delay minutes reported here.
Cancellations run at 3.03%, 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
8.3% 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 are the an hour and a half kind, which a normal layover absorbs.
The 1,188 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 68.9% on time across 2,306 flights, 9 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 9 points of difference.
The sample behind these figures is 2,307 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 3.03% cancellation rate. A late arrival costs you an hour and a half; a cancelled flight costs you the day. Book the 5am–8am departure so there is still a schedule behind you if it goes wrong, and treat a same-day connection as optimistic. 2,218 completed flights over 12 months sit behind that.
Common questions
ONT to DFW questions
How often is ONT to DFW delayed?
Roughly one flight in five arrive at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 21.8% of the 2,307 flights in this analysis, against 22.4% nationally. Delayed flights are late by an hour and a half on average.
How reliable is ONT to DFW compared with the rest of the country?
78.2% of flights arrive on time here against a national 77.6%, a difference of half a point in its favour. That is worth a B− on this site's grading scale.
What time of day has the fewest delays on ONT to DFW?
The 5am–8am departure window is the strongest at 89.1% on time. The 5pm–8pm window is the weakest at 67.1%, 22 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 July delays on ONT to DFW?
July is the weakest month at 65.7% on time, compared with 88.2% in April. Across the year that is 23 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
- DFW to ONT — the return legseparate record
- Dallas/Fort Worth International (DFW) delay statistics
- American Airlines on-time record78.6%
- Frontier Airlines on-time record75.6%
- Why the first flight of the morning is statistically safest
- What a cancellation rate actually tells you (and what it hides)
Direction matters. ONT to DFW and DFW to ONT 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.