Carrier route record
F9PHX→DEN
Frontier Airlines · Phoenix to Denver
- Flights
- 1,427
- Period
- July 2025 to June 2026
- Share of route
- 16%
- Carriers
- 6
Historical statistics for July 2025 to June 2026, not live status. For today’s flights, check with Frontier Airlines.
Frontier on PHX to DEN lands a B+, 2 points better than the national rate of 77.6%. About one flight in five arrives 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 1,427 flights. The strongest carrier on the route with a full sample, United Airlines, flew 2,370 at 83.5% on time.
United Airlines is the most reliable of the three carriers covered here at 83.5% on time across 2,370 flights.
Key figures
On time
80.0%
Arrivals under 15 minutes late, of 1,414 completed flights
Avg delay
88 min
Across delayed arrivals only, not all flights
Cancelled
0.63%
National rate is 1.81%
Whole route
77.2%
Every carrier on PHX to DEN, 8,920 flights
These figures cover 1,427 flights between July 2025 and June 2026. The median arrival is 9 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.
Carrier by carrier
Frontier against every carrier on PHX to DEN
Frontier flew 1,427 of the 8,920 flights on PHX to DEN, about 16% of it. Its 80.0% on time is 3 points better than the route as a whole, which runs 77.2%. Ranked by on-time rate it is number three of six carriers on the route, where the range runs from United at 83.5% to SkyWest at 66.7%. Two of those carriers flew fewer than 365 flights here, so treat their positions as rough.
The choice of carrier is not cosmetic here. United Airlines arrives on time 83.5% of the time; Southwest Airlines manages 72.8%. Sample sizes sit next to every figure, because a two-point gap across 3,942 flights means less than a ten-point one.
| Airline | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| United Airlines | 2,370 | 83.5% | 75 min | 0.59% | B+ |
| Envoy Airthin sample | 189 | 81.8% | 53 min | 0.53% | B+ |
| Frontier Airlines (this page) | 1,427 | 80.0% | 88 min | 0.63% | B+ |
| American Airlines | 974 | 74.8% | 66 min | 0.62% | C+ |
| Southwest Airlines | 3,942 | 72.8% | 56 min | 0.81% | C+ |
| SkyWest Airlinesthin sample | 18 | 66.7% | 98 min | 0.00% | C+ |
United leads Southwest by 11 points. Real, but small enough that a better departure time on the weaker carrier can outweigh it.
Flight by flight
Frontier flight numbers on PHX to DEN
Departure window
When Frontier runs best on this route
Departure time matters more here than the choice of carrier. The gap between the best and worst window is 20 points, against 11 points between the best and worst carrier. Each bar is the on-time rate for flights scheduled inside that window.
- 5am–8am304 flights87.8%
- 8am–11am283 flights85.3%
- 11am–2pm226 flights82.4%
- 2pm–5pm167 flights68.1%
- 5pm–8pm232 flights72.7%
- 8pm–5am215 flights76.6%
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 87.8% of the time, against 68.1% for the afternoon window. That is 20 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 304 flights scheduled in it.
Across the year
Frontier on PHX to DEN through the year
April is the best month on the calendar at 91.2% 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 164 flights.
Across the week, Saturday is the strongest day at 83.0% on time and Wednesday the weakest at 77.3%. 6 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. Late-arriving aircraft accounts for 64% of the 25,000 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.
- 64%Late-arriving aircraft
- 20%Carrier
- 15%National Airspace System
- 1%Extreme weather
64% 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 25,000 reported delay minutes here, that single category outweighs weather by 64 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 24,855 reported delay minutes.
The practical consequence: the 5am–8am departure is the one that starts clean. Its aircraft has no earlier leg to be late from, which is exactly why that window shows 87.8% on time here.
Cancellations are rare at 0.63%, below the national 1.81% 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 costs
7.6% 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 last an hour and a half, which a normal layover absorbs.
The 602 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 runs 77.4% on time across 1,432 flights, within 3 points of this direction. The two legs are scored separately because they usually differ; on this city pair they happen not to.
The sample behind these figures is 1,427 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 Frontier on PHX to DEN
Put together: the calendar is the biggest lever here, not the carrier or the hour. April runs 91.2% on time and March 69.3%, a swing of 22 points. If the dates move at all, move them out of March before you think about anything else. 1,414 completed flights over 12 months sit behind that.
Related
Where to go next
- PHX to DEN, every carrier
- Frontier on DEN to PHX, the return leg
- United Airlines on PHX to DEN83.5%
- Envoy Air on PHX to DEN81.8%
- American Airlines on PHX to DEN74.8%
- Southwest Airlines on PHX to DEN72.8%
- Frontier Airlines network-wide record
- Phoenix Sky Harbor International (PHX) delay statistics
- Denver International (DEN) delay statistics
- Why the first flight of the morning is statistically safest
- Same route, different airline: where the carrier you pick matters most
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.