Route reliability record
ONT→PHX
Ontario to Phoenix
- Flights
- 3,011
- Period
- September 2025 to August 2026
- Distance
- 325 mi
- Carriers
- 4
This route lands a B+, 5 points better than the national rate of 77.3%. About one flight in six arrives 15 minutes late or worse, and those flights are late by a little over an hour on average. That rests on 3,011 ONT to PHX flights, of which American Airlines flew 1,305 at 84.5% on time.
Best time to fly ONT to PHX: a 5am–8am departure, ideally on a Saturday. Flights in that window arrived on time 92.2% of the time and Saturday flights 85.3%, against 82.4% for the route overall.
Set against the rest of the country, this route's record is 5 points better than the US average of 77.3%. That gap is worth roughly 51 fewer late arrivals for every thousand flights.
Key figures
On time
82.4%
Arrivals under 15 minutes late, of 2,989 completed flights
Avg delay
72 min
Across delayed arrivals only, not all flights
Cancelled
0.63%
National rate is 1.89%
Best carrier
American
84.5% on time across 1,305 flights
These figures cover 3,011 flights between September 2025 and August 2026. The median arrival is 6 minutes early, which is the part an average hides: most flights here are fine, and the on-time rate is decided by a tail of badly late ones. On-time means under 15 minutes late, the DOT's own threshold.
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Carrier by carrier
Which airline is most reliable on ONT to PHX
The two carriers here are closely matched: 4 points separate the best from the worst. At that spread, schedule and price are better tie-breakers than reliability. Sample sizes are shown so you can see which rows are worth weighing.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| Envoy Airthin sample | 45 | 88.9% | 29 min | 0.00% | A+ |
| American Airlines | 1,305 | 84.5% | 108 min | 0.92% | B+ |
| SkyWest Airlinesthin sample | 46 | 82.2% | 40 min | 2.17% | B |
| Southwest Airlines | 1,615 | 80.5% | 50 min | 0.37% | B+ |
No carrier stands out. American tops the table at 84.5%, 4 points clear of the bottom, which is inside the range this kind of sample moves year to year.
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Best ways to make this trip
The most reliable ways to fly Ontario to Phoenix
Every airline on this route and on the routes between nearby airports, ranked by how often a scheduled flight actually operated and arrived on time. 4 of the top 5 use a different airport at one end.
| Option | Airline | Success | On time | Cancelled | Best departure | Most punctual flight |
|---|---|---|---|---|---|---|
| 1. LAX → PHXLos Angeles to Phoenix | SkyWest Airlines | 86.6% | 87.2% | 0.71% | 11am–2pm, Tue | OO 3894 14:19 |
| 2. BUR → PHXBurbank to Phoenix | Southwest Airlines | 83.9% | 84.8% | 1.02% | 8am–11am, Tue | — |
| 3. ONT → PHXOntario to Phoenix | American Airlines | 83.7% | 84.5% | 0.92% | 5am–8am, Sat | — |
| 4. SNA → PHXSanta Ana to Phoenix | Southwest Airlines | 82.3% | 82.9% | 0.67% | 5am–8am, Mon | — |
| 5. SNA → PHXSanta Ana to Phoenix | American Airlines | 81.1% | 81.6% | 0.62% | 8am–11am, Tue | AA 628 06:45 |
Success is the share of scheduled flights that operated and arrived less than 15 minutes late, so a cancelled flight counts against it. “(route)” means the best time comes from every carrier on the route rather than this airline alone.
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 26 points, against 4 points between the best and worst carrier.
- 5am–8am750 flights92.2%
- 8am–11am482 flights88.5%
- 11am–2pm608 flights84.4%
- 2pm–5pm512 flights71.2%
- 5pm–8pm500 flights76.0%
- 8pm–5am159 flights66.7%
Scale runs 60% to 100%.
Book the early departure. Flights leaving between 5am–8am arrive on time 92.2% of the time, against 66.7% for the overnight window. That is 26 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 750 flights scheduled in it.
Explore
Filter ONT to PHX by airline, time, month and day
Pick a breakdown and a carrier. The dashed mark on each row is the same slice for every US flight.
On ONT to PHX, the best departure window is 5am–8am at 92.2% on time and the worst is 8pm–5am at 66.7%, a wide gap of 25.5 points. All US flights leaving 5am–8am ran 89.3%.
- 5–8am92.2%
- 8–11am88.5%
- 11am–2pm84.4%
- 2–5pm71.2%
- 5–8pm76.0%
- 8pm–5am66.7%
best all US flightsScale 60% to 95%.
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.
May is the best month on the calendar at 87.8% on time. Shoulder season thins the schedule and takes the summer weather with it, and the operation gets its margin back. March was the busiest month here, with 289 flights.
Across the week, Saturday is the strongest day at 85.3% on time and Friday the weakest at 80.0%, a spread of 5 points.
Delay causes
Why this route gets delayed
Late-arriving aircraft accounts for 47% of the 37,000 delay minutes carriers reported here, and the remaining four split what is left.
- 47%Late-arriving aircraft
- 37%Carrier
- 15%National Airspace System
- 1%Extreme weather
- 0%Security
47% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 37,000 reported delay minutes here, that single category outweighs weather by 47 to one. The split is drawn from 37,262 reported delay minutes.
The largest share of delay minutes, 37%, falls under carrier control: crew scheduling, maintenance, fuelling, baggage. It accounts for 14,000 of the 37,000 delay minutes reported here.
Cancellations are rare at 0.63%, below the national 1.89% and low enough to earn the plus on the grade. Roughly one flight in 100 is called off; the risk here is arriving late, not not arriving.
Connections and stage length
What a delay here actually costs
5.1% 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 a little over an hour, which a normal layover absorbs.
At 325 miles this is a short hop, and stage length matters more than it looks. A flight this short spends under two hours in the air, which leaves almost nothing to claw back a late pushback with. Delay here is decided on the ground, in the turn, which is why the 5am–8am window matters as much as it does.
The return leg is a different operation and performs like one: it runs 76.8% on time across 3,012 flights, 6 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 6 points of difference.
The sample behind these figures is 3,011 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.
Work out the risk of missing a connection in PHX after this flight
What to do with this
Booking this route
Put together: the calendar is the biggest lever here, not the carrier or the hour. May runs 87.8% on time and November 73.6%, a swing of 14 points. If the dates move at all, move them out of November before you think about anything else. 2,989 completed flights over 12 months sit behind that.
Common questions
ONT to PHX questions
How often is ONT to PHX delayed?
About one flight in six arrives at least 15 minutes late, which is the Department of Transportation's definition of a delayed arrival. That works out to 17.6% of the 3,011 flights in this analysis, against 22.7% nationally. Delayed flights are late by a little over an hour on average.
Which airline is most reliable on ONT to PHX?
American Airlines leads at 84.5% on time across 1,305 flights. Southwest Airlines is at the other end on 80.5%, a gap of 4 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 ONT to PHX?
The 5am–8am departure window is the strongest at 92.2% on time. The 8pm–5am window is the weakest at 66.7%, 26 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 November delays on ONT to PHX?
November is the weakest month at 73.6% on time, compared with 87.8% in May. 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
- PHX to ONT — the return legseparate record
- Ontario International (ONT) delay statistics
- Phoenix Sky Harbor International (PHX) delay statistics
- American Airlines on ONT to PHX84.5%
- Southwest Airlines on ONT to PHX80.5%
- ONT to DEN, a related route81.8%
- DEN to PHX, a related route75.6%
- ONT to SEA, a related route85.9%
- Envoy Air on-time record88.9%
- American Airlines on-time record84.5%
- SkyWest Airlines on-time record82.2%
- 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. ONT to PHX and PHX to ONT are scored separately because they are separate operations, with different departure banks and different aircraft. Compare the return leg.
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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.