Flight profile · Frontier Airlines
F91375
Denver (DEN) to Phoenix (PHX) · scheduled 6:00 AM – 8:12 AM
How F91375 performs
624 operations, January 2024 – June 2026.
F91375 arrived on time 83.6% of the time, against 75.8% for all DEN → PHX flights, so this departure is 7.8 percentage points better than the route as a whole. Against Frontier Airlines’ own flights on this route it is 8.6 points better.
Source: US DOT Bureau of Transportation Statistics · 624 operations, January 2024 – June 2026 · If F91375 is cancelled or significantly changed, DOT’s automatic refund rule may entitle you to your money back. The refund checker walks through eligibility.
Where F91375 is right now
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Against the rest of the route
| Flight or route | On time | Cancelled | Median delay | Severe | Flights |
|---|---|---|---|---|---|
| F91375 | 83.6% | 1.12% | -8 min | 4.1% | 624 |
| Frontier Airlines on DEN → PHX | 75.0% | 0.62% | -4 min | 9.2% | 4,695 |
| All DEN → PHX flights | 75.8% | 0.90% | -4 min | 7.9% | 28,387 |
Source: FlyerIntel analysis of US DOT BTS data · January 2024 – June 2026
Why F91375 runs late
Where US DOT attributed the delay minutes on this flight.
crew, maintenance, boarding and fueling, all within the carrier’s control
airspace and airport capacity, including weather-driven flow control
the inbound aircraft was late, so this flight started late
weather severe enough to stop this flight specifically
Share of the delay minutes US DOT attributed to each cause for F91375 on DEN → PHX. Only delays of 15 minutes or more are attributed.
Source: US DOT Bureau of Transportation Statistics · Data covering January 2024 – June 2026
Does a late aircraft delay this flight?
How often the plane that flies F91375 comes in late, and what that does to the departure.
F91375 is usually the aircraft’s first flight of the day: the schedule gives it a median of 6 hours on the ground at DEN, so its “inbound” is mostly the aircraft’s arrival the evening before.
When the aircraft came in 15 or more minutes late, F91375 pushed back an average of 4 minutes late; when it came in on time or early, an average of 1 minute late.
Each departure is matched to the flight the same aircraft flew into DEN just before it, using the tail number in the DOT file, 492 of 617 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 |
|---|---|---|---|
| F91375 | 27% | 15% | 11% |
| Network, same turn | 29% | 12% | 9% |
A night on the ground absorbs most of a late arrival, so a late inbound matters far less on a turn this long than on a same-day one.
The network row is every flight with a scheduled turn of 6 hours or more, usually overnight. How often F91375’s aircraft landed 15 or more minutes late is about the same as the network’s and, once the aircraft was late, how often F91375 left 15 or more minutes late is about the same as 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 January 2024 – June 2026
From pushback to gate
When it leaves DEN late, does that still matter by the time it reaches PHX?
F91375 pushes back an average of 4.7 minutes late and reaches the gate at PHX an average of 1.3 minutes late. The 3.4 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 19.7 minutes on the taxiways at DEN, 1.5 minutes longer than a typical DEN departure in the same hour.
On arrival at PHX, F91375 spends 9.7 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 2.3 minutes longer than a typical PHX arrival (7.5 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 PHX. Taxi-out is gate to wheels up and sits inside the scheduled block rather than on top of it; the comparison is 33,948 departures from DEN scheduled in the clock hour F91375 most often leaves in. Taxi-in is landing to gate, compared against every arrival FlyerIntel has on file at PHX (598,496 flights), not just F91375’s own. More on taxi time.
Source: FlyerIntel analysis of US DOT BTS data · January 2024 – June 2026
The hour it leaves DEN
Part of any flight’s record belongs to the clock rather than to the flight. F91375 has one departure time, so this is what that time is worth.
On-time arrival rate. 33,948 departures from DEN are scheduled in the 6 AM–7 AM hour over the period, against 963,099 across the whole day.
F91375 is scheduled out of DEN at 6:00 AM, in the 6 AM–7 AM bank. Departures from DEN in that hour arrive on time 90.8% of the time against 76.0% across the airport’s whole day — the slot alone is worth 14.7 points better before anything about this particular flight is considered.
The two airport figures cover every departure from DEN 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 · January 2024 – June 2026 · Hours below 120 departures are not scored.
Other routes F91375 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 |
|---|---|---|---|
| MDW→PHX Chicago to Phoenix | July 1, 2023 – November 15, 2023 | 100 | 80.4% |
Because the same number has served different journeys, the statistics above describe only the route F91375 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 8 min early
Percentiles over 624 operations; cancelled and diverted flights are counted separately.
Source: US DOT Bureau of Transportation Statistics · Data covering January 2024 – June 2026
Other flights on this route
Same airports, same journey, different odds of arriving on time.
| Flight | Airline | On time | Median arrival | Operations |
|---|---|---|---|---|
| UA1481 | United Airlines | 83.8% | 8 min early | 825 |
| F91375 this flight | Frontier Airlines | 83.6% | 8 min early | 624 |
| UA2249 | United Airlines | 78.3% | 6 min early | 815 |
| AA1404 | American Airlines | 77.4% | 3 min early | 1,095 |
| UA594 | United Airlines | 75.9% | 5 min early | 610 |
| F94753 | Frontier Airlines | 62.1% | 4 min late | 705 |
Every departure listed carries at least 600 operations, so the comparison is between figures that mean something. F91375 is placed in the same ordering rather than left out of it; the rows around it are the most punctual departures on the route, not all of them, so this is a comparison and not a rank. Schedules change; confirm the departure still operates before booking around this.
Data and methodology
Calculated by FlyerIntel from 624 records of F91375 operating DEN → PHX, 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