Carrier route record
F9DEN→PHL
Frontier Airlines · Denver to Philadelphia
- Flights
- 295
- Period
- July 2025 to June 2026
- Share of route
- 10%
- Carriers
- 4
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Frontier Airlines.
Frontier on DEN to PHL draws a D. Roughly one flight in three arrives at least 15 minutes late, and the typical late arrival is close to two hours behind schedule. Build slack into anything you connect to. That rests on 295 flights. The strongest carrier on the route with a full sample, United Airlines, flew 952 at 79.9% on time.
United Airlines is the most reliable of the three carriers covered here at 79.9% on time across 952 flights.
Key figures
On time
62.3%
Arrivals under 15 minutes late, of 289 completed flights
Avg delay
103 min
Across delayed arrivals only, not all flights
Cancelled
2.03%
National rate is 1.81%
Whole route
73.1%
Every carrier on DEN to PHL, 3,003 flights
These figures cover 295 flights between July 2025 and June 2026. Beyond the headline rate, 15.6% 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
Frontier against every carrier on DEN to PHL
Frontier flew 295 of the 3,003 flights on DEN to PHL, about 10% of it. Its 62.3% on time is 11 points worse than the route as a whole, which runs 73.1%. Ranked by on-time rate it is last of four carriers on the route, where the range runs from United at 79.9% to Frontier at 62.3%.
The choice of carrier is not cosmetic here. United Airlines arrives on time 79.9% of the time; Southwest Airlines manages 63.7%. Sample sizes sit next to every figure, because a two-point gap across 879 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 952 | 79.9% | 66 min | 0.53% | B+ |
| American Airlines | 877 | 78.8% | 103 min | 1.82% | B |
| Southwest Airlines | 879 | 63.7% | 58 min | 0.91% | D+ |
| Frontier Airlines (this page)thin sample | 295 | 62.3% | 103 min | 2.03% | D |
The spread between United and Southwest is 16 points, wide enough that it should decide the booking. On a hundred trips that is 16 more arrivals inside the on-time window.
Departure window
When Frontier runs best on this route
Departure time is the single lever a traveller controls, and it moves the odds more than most people expect. Each bar below is the on-time rate for flights scheduled to leave inside that window, across 295 flights.
The overnight block holds up unusually well at 60.4% on time across 211 flights. Red-eyes fly into empty airspace and empty gates, and they are the first rotation of the aircraft's day rather than the last. The 8pm–5am window is the busiest, with 211 flights scheduled in it.
Across the year
Frontier on DEN to PHL through the year
- Jul–Sep 2025101 flights57.0%
- Oct–Dec 202557 flights67.3%
- Jan–Mar 202637 flights45.7%
- Apr–Jun 2026100 flights70.7%
Scale runs 35% to 75%. Rows with fewer than 30 flights show a dash.
Monthly volumes are too low here to break the year into twelve reliable readings. What the twelve-month total says is 62.3% on time across 295 flights.
Frontier on DEN to PHL did not run the same all year. Its best quarter was Apr–Jun 2026 at 70.7% on time and its weakest Jan–Mar 2026 at 45.7%, a swing of 25 points on roughly 74 flights a quarter. The twelve-month rate averages over that, so if you are flying in a weak quarter the quarter's own figure is the better guide.
Across the week, Wednesday is the strongest day at 82.9% on time and Monday the weakest at 47.7%. 35 points is a smaller lever than departure hour, but it is free.
Delay causes
Why Frontier runs late on this route
One category carries most of the weight here. Carrier accounts for 66% of the 11,000 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.
- 66%Carrier
- 21%Late-arriving aircraft
- 12%National Airspace System
- 1%Extreme weather
The largest share of delay minutes, 66%, 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 7,328 of the 11,000 delay minutes reported here. The split is drawn from 11,174 reported delay minutes.
Cancellations sit at 2.03% against a national 1.81%, which is ordinary. Diversions add another 0.00%.
Connections and stage length
What a delay here costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 15.6% of arrivals land a full hour or more behind schedule, against 8.1% nationally. A 45-minute layover does not survive that, and no amount of walking quickly changes it. Ninety minutes is the honest minimum here, and two hours if the onward flight is on a separate ticket.
At 1,558 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 68.4% on time across 296 flights, 6 points above 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.
One caution: this is a thin sample. 295 flights over twelve months is enough to clear this site's floor but not enough to pin the rate down tightly, and a single bad week moves it by more than a point. Treat the grade as a rough reading.
What to do with this
Booking Frontier on DEN to PHL
Put together: treat all of this as provisional. 295 flights over twelve months is enough to clear this site's floor and not enough to be confident to better than a couple of points. The 62.3% headline is the most reliable number on the page; the hour and month splits below it are built on a few dozen flights each. 289 completed flights over 12 months sit behind that.
Related
Where to go next
- DEN to PHL, every carrier
- Frontier on PHL to DEN, the return leg
- United Airlines on DEN to PHL79.9%
- American Airlines on DEN to PHL78.8%
- Southwest Airlines on DEN to PHL63.7%
- Frontier Airlines network-wide record
- Denver International (DEN) delay statistics
- Philadelphia International (PHL) delay statistics
- Same route, different airline: where the carrier you pick matters most
- How often a connection fails at the major US hubs
Source: US DOT Bureau of Transportation Statistics, on-time performance data, July 2025 to June 2026. Last updated 15 September 2026; recomputed monthly. How this data is collected.