Flight number record
F9 1261
Frontier Airlines · Denver to Ontario
- Route
- DEN → ONT
- Departs
- 22:29
- Flights
- 270
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s F9 1261, check with Frontier Airlines.
F9 1261 lands a B+, level with the national rate of 77.3%. Roughly one flight in four arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 270 flights, with a median arrival 8 minutes early.
Key figures
On time
76.9%
Arrivals under 15 minutes late, of 268 completed flights
Avg delay
68 min
Across delayed arrivals only, not all flights
Cancelled
0.74%
National rate is 1.89%
1 hour+ late
9.0%
National rate is 8.3%
These figures cover 270 flights between September 2025 and August 2026. Beyond the headline rate, 9.0% of arrivals land a full hour or more behind schedule, against 8.3% nationally.
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Schedule
When F9 1261 flies
F9 1261 flies DEN to ONT without a single fixed slot. Its most common scheduled departure was 22:29, used on 166 of 270 flights.
- Departs 22:29166 flights61.5%
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 22:29 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.1%, and F9 1261 runs 7 points better at 76.9%. 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 1261 next to DEN to ONT
Every carrier on DEN to ONT combined arrived on time 74.8% of the time across 2,623 flights, so F9 1261 is 2 points ahead of it. Frontier flew 557 flights on the same city pair under all its flight numbers, including this one, and those ran 80.3% on time. Across its whole network Frontier Airlines managed 72.7%, which this flight beats by 4 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| F9 1261thin sample | 270 | 76.9% | 68 min | 0.74% | B+ |
| All Frontier Airlines on DEN–ONT | 557 | 80.3% | 61 min | 0.54% | B+ |
| All carriers on DEN–ONT | 2,623 | 74.8% | 57 min | 0.19% | C+ |
| Frontier Airlines, whole network | 213,022 | 72.7% | 84 min | 2.05% | C |
Across the year
F9 1261 quarter by quarter
F9 1261 did not run the same all year. Its best quarter was Oct–Dec 2025 at 92.2% on time and its weakest Jul–Sep 2026 at 66.7%, a swing of 26 points on roughly 68 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 202517 flights—
- Oct–Dec 202551 flights92.2%
- Jan–Mar 202649 flights81.6%
- Apr–Jun 202691 flights69.2%
- Jul–Sep 202662 flights66.7%
Scale runs 60% to 100%. Rows with fewer than 30 flights show a dash.
By weekday, F9 1261 did best on Sunday at 85.4% on time and worst on Monday at 64.3%. Each day rests on about 39 flights, so a gap of 21 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late F9 1261 runs when it is late
F9 1261 often beats the schedule: 87 of 268 completed flights, 32%, arrived 15 minutes or more early. The 62 late arrivals split 18 under half an hour, 20 between 30 and 60 minutes, and 24 an hour or more.
- 15+ min early87 flights32.5%
- Within 15 min119 flights44.4%
- 15–29 min late18 flights6.7%
- 30–59 min late20 flights7.5%
- 1–2 hours late21 flights7.8%
- 2+ hours late3 flights1.1%
Scale runs 0% to 100%.
Share of 268 completed flights by arrival against schedule.
16 of 71 late departures made up the time and arrived on time, 23% of them. 7 flights left on time and still arrived late.
The worst days
Worst days for F9 1261
The latest arrival of the period was on 6 March 2026, 9 hours 9 minutes behind schedule; most of its delay minutes were filed as carrier-caused (crew, maintenance, fuelling, baggage). The same cause led on three of the five worst days.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 6 March 2026 | 9 hours 9 minutes | Carrier |
| 20 April 2026 | 7 hours 10 minutes | Carrier |
| 28 July 2026 | 2 hours 6 minutes | Late-arriving aircraft |
| 1 September 2025 | 1 hour 57 minutes | Carrier |
| 29 July 2026 | 1 hour 54 minutes | Late-arriving aircraft |
Delay causes
Why F9 1261 runs late
Carrier accounts for 51% of the 4,189 delay minutes carriers reported here, and the remaining four split what is left.
- 51%Carrier
- 40%Late-arriving aircraft
- 7%National Airspace System
- 2%Extreme weather
40% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 4,189 reported delay minutes here, that single category outweighs weather by 19 to one. The split is drawn from 4,189 delay minutes reported on F9 1261.
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
9.0% 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 819 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 1261 in the data flew DEN to ONT. 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 1261
For a booking, read F9 1261 as 76.9% on time with 0.74% cancelled over 270 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- DEN to ONT, every carrier and departure
- ONT to DEN, the return direction
- United Airlines 430 on the same route87.6%
- Denver International (DEN) delay statistics
- Ontario International (ONT) 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.