Flight number record
F9 4567
Frontier Airlines · St. Louis to Denver
- Route
- STL → DEN
- Departs
- 20:08
- Flights
- 270
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s F9 4567, check with Frontier Airlines.
F9 4567 sits in the middle of the pack with a C+. Close to three flights in four arrive on time by the DOT's definition, 4 points worse than the national rate of 77.3%. The late ones land an hour and a half behind schedule. That rests on 270 flights, with a median arrival 9 minutes early.
Key figures
On time
73.5%
Arrivals under 15 minutes late, of 268 completed flights
Avg delay
90 min
Across delayed arrivals only, not all flights
Cancelled
0.74%
National rate is 1.89%
1 hour+ late
12.3%
National rate is 8.3%
These figures cover 270 flights between September 2025 and August 2026. Beyond the headline rate, 12.3% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When F9 4567 flies
F9 4567 flies STL to DEN without a single fixed slot. Its most common scheduled departure was 20:08, used on 81 of 270 flights, with 19:55 (33 flights) and 19:43 (31 flights) next.
- Departs 20:0881 flights30.0%
- Departs 19:5533 flights12.2%
- Departs 19:4331 flights11.5%
Scale runs 0% to 100%.
Share of scheduled departures at each local time. Times used on fewer than one flight in ten are not listed.
A 20:08 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.1%, and F9 4567 runs 3 points better at 73.5%. By that time of day most aircraft have flown several legs already, and whatever went wrong earlier is still in the schedule.
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Against the route
F9 4567 next to STL to DEN
Every carrier on STL to DEN combined arrived on time 75.0% of the time across 3,687 flights, so F9 4567 is 2 points behind it. Across its whole network Frontier Airlines managed 72.7%, close to this flight's figure.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| F9 4567thin sample | 270 | 73.5% | 90 min | 0.74% | C+ |
| All Frontier Airlines on STL–DENthin sample | 292 | 74.5% | 90 min | 0.68% | C+ |
| All carriers on STL–DEN | 3,687 | 75.0% | 69 min | 0.33% | B+ |
| Frontier Airlines, whole network | 213,022 | 72.7% | 84 min | 2.05% | C |
Across the year
F9 4567 quarter by quarter
F9 4567 did not run the same all year. Its best quarter was Oct–Dec 2025 at 84.6% on time and its weakest Jan–Mar 2026 at 61.3%, a swing of 23 points on roughly 54 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 202530 flights83.3%
- Oct–Dec 202579 flights84.6%
- Jan–Mar 202631 flights61.3%
- Apr–Jun 202674 flights68.5%
- Jul–Sep 202656 flights66.1%
Scale runs 55% to 90%.
By weekday, F9 4567 did best on Sunday at 84.8% on time and worst on Friday at 58.3%. Each day rests on about 39 flights, so a gap of 27 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late F9 4567 runs when it is late
F9 4567 often beats the schedule: 107 of 268 completed flights, 40%, arrived 15 minutes or more early. The 71 late arrivals split 20 under half an hour, 18 between 30 and 60 minutes, and 33 an hour or more.
- 15+ min early107 flights39.9%
- Within 15 min90 flights33.6%
- 15–29 min late20 flights7.5%
- 30–59 min late18 flights6.7%
- 1–2 hours late20 flights7.5%
- 2+ hours late13 flights4.9%
Scale runs 0% to 100%.
Share of 268 completed flights by arrival against schedule.
11 of 71 late departures made up the time and arrived on time, 15% of them. 11 flights left on time and still arrived late.
The worst days
Worst days for F9 4567
The latest arrival of the period was on 23 August 2026, 13 hours 57 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). Three of the five worst days fell in August 2026.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 23 August 2026 | 13 hours 57 minutes | Carrier |
| 5 January 2026 | 11 hours 12 minutes | Late-arriving aircraft |
| 23 March 2026 | 5 hours 15 minutes | Late-arriving aircraft |
| 14 August 2026 | 3 hours 56 minutes | Late-arriving aircraft |
| 13 August 2026 | 3 hours 51 minutes | National Airspace System |
Delay causes
Why F9 4567 runs late
Late-arriving aircraft accounts for 54% of the 6,395 delay minutes carriers reported here, and the remaining four split what is left.
- 54%Late-arriving aircraft
- 24%National Airspace System
- 21%Carrier
- 1%Extreme weather
54% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 6,395 reported delay minutes here, that single category outweighs weather by 54 to one. The split is drawn from 6,395 delay minutes reported on F9 4567.
Cancellations are rare at 0.74%, below the national 1.89% 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
12.3% of arrivals land a full hour or more behind schedule, against 8.3% nationally. Ninety minutes is the honest minimum for a connection here, and two hours if the onward flight is on a separate ticket.
The 770 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.
Every one of the 270 flights under F9 4567 in the data flew STL to DEN. 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. 270 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 4567
For a booking, F9 4567 is a flight to put a long connection behind. 12.3% of its completed flights arrived an hour or more late, which a short layover will not absorb. If the onward flight is on a separate ticket, the risk sits with you.
Related
Where to go next
- STL to DEN, every carrier and departure
- DEN to STL, the return direction
- St. Louis Lambert International (STL) delay statistics
- Denver International (DEN) 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
- Why the first flight of the morning is statistically safest
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, September 2025 to August 2026. Last updated ; recomputed monthly. How this data is collected.