Flight number record
F9 4345
Frontier Airlines · Denver to Los Angeles
- Route
- DEN → LAX
- Departs
- 22:55
- Flights
- 305
- Period
- July 2025 to June 2026
Historical statistics for July 2025 to June 2026, not live status. For today’s F9 4345, check with Frontier Airlines.
F9 4345 sits in the middle of the pack with a C+. About seven flights in ten arrive on time by the DOT's definition, 6 points worse than the national rate of 77.6%. The late ones land a little over an hour behind schedule. That rests on 305 flights, with a median arrival 7 minutes early.
The national on-time rate over the same period is 77.6%, so F9 4345 runs 6 points behind the country as a whole. Across a thousand flights that is about 63 extra late arrivals.
Key figures
On time
71.3%
Arrivals under 15 minutes late, of 303 completed flights
Avg delay
73 min
Across delayed arrivals only, not all flights
Cancelled
0.66%
National rate is 1.81%
1 hour+ late
10.6%
National rate is 8.1%
These figures cover 305 flights between July 2025 and June 2026. Beyond the headline rate, 10.6% 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.
Schedule
When F9 4345 flies
F9 4345 flies DEN to LAX without a single fixed slot. Its most common scheduled departure was 22:55, used on 135 of 305 flights, with 22:29 (54 flights) and 22:39 (49 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.
- Departs 22:55135 flights44.3%
- Departs 22:2954 flights17.7%
- Departs 22:3949 flights16.1%
Scale runs 0% to 100%. Rows with fewer than 30 flights show a dash.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 22:55 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.5%, and F9 4345 runs level with that at 71.3%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.
Against the route
F9 4345 next to DEN to LAX
Every carrier on DEN to LAX combined arrived on time 79.0% of the time across 7,721 flights, so F9 4345 is 8 points behind it. Frontier flew 762 flights on the same city pair under all its flight numbers, including this one, and those ran 81.1% on time. Across its whole network Frontier Airlines managed 73.2%, which this flight trails by 2 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| F9 4345thin sample | 305 | 71.3% | 73 min | 0.66% | C+ |
| All Frontier Airlines on DEN–LAX | 762 | 81.1% | 75 min | 0.52% | B+ |
| All carriers on DEN–LAX | 7,721 | 79.0% | 62 min | 0.51% | B+ |
| Frontier Airlines, whole network | 205,332 | 73.2% | 84 min | 1.85% | C |
Across the year
F9 4345 quarter by quarter
F9 4345 did not run the same all year. Its best quarter was Oct–Dec 2025 at 77.5% on time and its weakest Jul–Sep 2025 at 58.8%, a swing of 19 points on roughly 76 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.
- Jul–Sep 202586 flights58.8%
- Oct–Dec 202580 flights77.5%
- Jan–Mar 202665 flights75.4%
- Apr–Jun 202674 flights75.3%
Scale runs 50% to 85%. Rows with fewer than 30 flights show a dash.
By weekday, F9 4345 did best on Wednesday at 82.4% on time and worst on Saturday at 62.5%. Each day rests on about 44 flights, so a gap of 20 points is worth noticing but could still narrow in another year.
Delay causes
Why F9 4345 runs late
One category carries most of the weight here. Carrier accounts for 64% of the 6,371 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%Carrier
- 28%Late-arriving aircraft
- 8%National Airspace System
- 1%Extreme weather
The largest share of delay minutes, 64%, 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 4,046 of the 6,371 delay minutes reported here. The split is drawn from 6,371 delay minutes reported on F9 4345.
Cancellations are rare at 0.66%, 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 routes
What a delay on this flight costs
For anyone connecting, the number to weigh is not the on-time rate but the tail behind it. 10.6% 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.
The 862 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.
Every one of the 305 flights under F9 4345 in the data flew DEN to LAX. The number was not reused on any other city pair, which makes this a clean record of one route.
One caution: this is a thin sample. 305 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 F9 4345
For a booking, F9 4345 is one of the weaker ways to fly DEN to LAX: 8 points below the route as a whole. If the schedule allows, compare it with the other departures listed on the route page before settling on this one.
Related
Where to go next
- DEN to LAX, every carrier and departure
- LAX to DEN, the return direction
- United Airlines 1638 on the same route91.2%
- United Airlines 1013 on the same route86.3%
- United Airlines 405 on the same route91.0%
- United Airlines 2240 on the same route75.9%
- Frontier Airlines 2341 on the same route89.3%
- United Airlines 531 on the same route80.1%
- Denver International (DEN) delay statistics
- Los Angeles International (LAX) delay statistics
- Frontier Airlines on-time record
- Every Frontier Airlines flight number with a record
- The most and least reliable flight numbers in the US
- How often a connection fails at the major US hubs
A flight number here means Frontier Airlines’s own number as it reports to the DOT. How the figures are computed is on the methodology page.
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.