Flight profile · Frontier Airlines
F91500
Ontario (ONT) to Denver (DEN) · scheduled 12:59 AM – 4:19 AM
How F91500 performs
828 operations, November 2023 – July 2026.
F91500 arrived on time 85.3% of the time, against 82.3% for all ONT → DEN flights, so this departure is 3.0 percentage points better than the route as a whole. Against Frontier Airlines’ own flights on this route it is 5.6 points better.
Source: US DOT Bureau of Transportation Statistics · 828 operations, November 2023 – July 2026 · If F91500 is cancelled or significantly changed, DOT’s automatic refund rule may entitle you to your money back. The refund checker walks through eligibility.
Where F91500 is right now
A live reading, only if you ask for it. It is not part of the reliability record above.
Ask for the position of F91500 right now, if receivers on the ground are hearing it. Nothing is requested until you press the button.
Against the rest of the route
| Flight or route | On time | Cancelled | Median delay | Severe | Flights |
|---|---|---|---|---|---|
| F91500 | 85.3% | 0.60% | -9 min | 5.2% | 828 |
| Frontier Airlines on ONT → DEN | 79.7% | 1.12% | -8 min | 8.2% | 1,972 |
| All ONT → DEN flights | 82.3% | 0.73% | -8 min | 6.6% | 8,674 |
Source: FlyerIntel analysis of US DOT BTS data · November 2023 – July 2026
Why F91500 runs late
Where US DOT attributed the delay minutes on this flight.
the inbound aircraft was late, so this flight started late
airspace and airport capacity, including weather-driven flow control
crew, maintenance, boarding and fueling, all within the carrier’s control
weather severe enough to stop this flight specifically
Share of the delay minutes US DOT attributed to each cause for F91500 on ONT → DEN. Only delays of 15 minutes or more are attributed.
Source: US DOT Bureau of Transportation Statistics · Data covering November 2023 – July 2026
Does a late aircraft delay this flight?
How often the plane that flies F91500 comes in late, and what that does to the departure.
When the aircraft came in 15 or more minutes late, F91500 pushed back an average of 25 minutes late; when it came in on time or early, an average of 2 minutes early.
Each departure is matched to the flight the same aircraft flew into ONT just before it, using the tail number in the DOT file, 815 of 823 departures in all. A departure is left out when that flight is unknown, was cancelled or diverted, or the aircraft had sat for more than 12 hours. A flight the airline cancelled never left and is not in the count, and one flown by a substitute aircraft is matched to the aircraft that flew it, not to the one first planned.
Against the network at the same turn length
| Share of departures | Inbound landed 15+ late | Left 15+ late after a late inbound | Left 15+ late after an on-time inbound |
|---|---|---|---|
| F91500 | 27% | 36% | 6% |
| Network, same turn | 17% | 68% | 9% |
The schedule leaves a normal turn: enough time to clean and board if the aircraft is on time, little to spare if it is not.
The network row is every flight with a scheduled turn of 60 to 89 minutes. How often F91500’s aircraft landed 15 or more minutes late is higher than the network’s and, once the aircraft was late, how often F91500 left 15 or more minutes late is lower than the network’s.
More: Which Flight Numbers Pay for a Late Aircraft lists the flight numbers that pass a late aircraft on.
Source: US DOT Bureau of Transportation Statistics · Data covering November 2023 – July 2026
From pushback to gate
When it leaves ONT late, does that still matter by the time it reaches DEN?
F91500 pushes back an average of 6.7 minutes late and reaches the gate at DEN an average of 1.4 minutes late. The 5.2 minutes between those two figures are slack the published schedule already carries, which is why a late pushback on this flight does not reliably become a late arrival. It spends 14.2 minutes on the taxiways at ONT, 1.5 minutes longer than a typical ONT departure in the same hour.
On arrival at DEN, F91500 spends 15.4 min taxiing from touchdown to the gate — ground time a connecting passenger sits through before they can even leave the aircraft, on top of however late the flight itself ran. That is 5.6 minutes longer than a typical DEN arrival (9.8 min).
Departure delay is averaged over every pushback and arrival delay over every completed arrival, so the two counts differ by the flights that never reached DEN. Taxi-out is gate to wheels up and sits inside the scheduled block rather than on top of it; the comparison is 618 departures from ONT scheduled in the clock hour F91500 most often leaves in. Taxi-in is landing to gate, compared against every arrival FlyerIntel has on file at DEN (963,027 flights), not just F91500’s own. More on taxi time.
Source: FlyerIntel analysis of US DOT BTS data · November 2023 – July 2026
The hour it leaves ONT
Part of any flight’s record belongs to the clock rather than to the flight. F91500 has one departure time, so this is what that time is worth.
On-time arrival rate. 618 departures from ONT are scheduled in the 12 AM–1 AM hour over the period, against 79,949 across the whole day.
F91500 is scheduled out of ONT at 12:59 AM, in the 12 AM–1 AM bank. Departures from ONT in that hour arrive on time 79.7% of the time against 83.5% across the airport’s whole day — the slot alone is worth 3.8 points worse before anything about this particular flight is considered.
The two airport figures cover every departure from ONT to every destination, so they describe the slot rather than this journey — the like-for-like comparison against the route is above. Hours are scheduled local, and a number whose schedule moved between banks inside the period has no single hour and is not described here at all. Why the hour matters.
Source: FlyerIntel analysis of US DOT BTS data · November 2023 – July 2026 · Hours below 120 departures are not scored.
Other routes F91500 has flown
A flight number is a slot in a schedule, and carriers reassign it. These are the other city pairs this number served in the analysis period.
| Route | Operated | Flights | On time |
|---|---|---|---|
| DEN→FSD Denver to Sioux Falls | April 10, 2024 – May 15, 2024 | 6 | — |
| DEN→MSP Denver to Minneapolis | April 13, 2024 – May 11, 2024 | 4 | — |
Because the same number has served different journeys, the statistics above describe only the route F91500 currently operates. Blending them would produce an average of two different flights.
When it goes wrong
The average describes a usual day. This is the day that ruins a connection.
27 min late
against a median of 9 min early
Percentiles over 828 operations; cancelled and diverted flights are counted separately.
Source: US DOT Bureau of Transportation Statistics · Data covering November 2023 – July 2026
Data and methodology
Calculated by FlyerIntel from 828 records of F91500 operating ONT → DEN, published by the US DOT Bureau of Transportation Statistics. A flight counts as delayed when it arrives 15 or more minutes after schedule. Cancelled and diverted flights are excluded from the on-time rate and reported separately. Flight numbers are resolved as carrier plus number plus route, because the same number serves different routes over time.
Full methodology · Data sources · Report a problem
Related research: Most and Least Reliable Flight Numbers · The Delay You Inherit · Making Up Time in the Air
Analysis last recomputed