Flight number record

F9 1500

Frontier Airlines · Ontario to Denver

Route: ONT → DEN
Departs: 00:59
Flights: 320
Period: July 2025 to June 2026

Historical statistics for July 2025 to June 2026, not live status. For today’s F9 1500, check with Frontier Airlines.

F9 1500 earns an A+. More than four flights in five arrive inside the 15-minute window the DOT uses to define an on-time arrival, which puts it 9 points better than the national rate of 77.6%. When something does go wrong the average delay runs a little over an hour. That rests on 320 flights, with a median arrival 8 minutes early.

Set against the rest of the country, F9 1500's record is 9 points better than the US average of 77.6%. That gap is worth roughly 86 fewer late arrivals for every thousand flights.

On time

86.2%

Arrivals under 15 minutes late, of 318 completed flights

Avg delay

77 min

Across delayed arrivals only, not all flights

Cancelled

0.62%

National rate is 1.81%

1 hour+ late

5.3%

National rate is 8.1%

These figures cover 320 flights between July 2025 and June 2026. The median arrival is 8 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.

Schedule

When F9 1500 flies

F9 1500 flies ONT to DEN without a single fixed slot. Its most common scheduled departure was 00:59, used on 87 of 320 flights, with 06:00 (67 flights) next. Carriers retime flights through the season, so the rates here blend slightly different positions in the aircraft's day.

Departs 00:5987 flights27.2%
Departs 06:0067 flights20.9%

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 00:59 departure sits in the 8pm–5am window. Across every US flight scheduled in that window the on-time rate is 70.5%, and F9 1500 runs 16 points better at 86.2%. 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 1500 next to ONT to DEN

Every carrier on ONT to DEN combined arrived on time 79.7% of the time across 2,672 flights, so F9 1500 is 7 points ahead of it. Frontier flew 552 flights on the same city pair under all its flight numbers, including this one, and those ran 80.1% on time. Across its whole network Frontier Airlines managed 73.2%, which this flight beats by 13 points.

F9 1500 against its route and carrier
Compared with	Flights	On time	Avg delay	Cancelled	Grade
F9 1500thin sample	320	86.2%	77 min	0.62%	A+
All Frontier Airlines on ONT–DEN	552	80.1%	98 min	0.72%	B+
All carriers on ONT–DEN	2,672	79.7%	70 min	0.45%	B+
Frontier Airlines, whole network	205,332	73.2%	84 min	1.85%	C

Across the year

F9 1500 quarter by quarter

F9 1500 did not run the same all year. Its best quarter was Apr–Jun 2026 at 95.6% on time and its weakest Jul–Sep 2025 at 72.3%, a swing of 23 points on roughly 80 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 202566 flights72.3%
Oct–Dec 202573 flights87.5%
Jan–Mar 202690 flights85.6%
Apr–Jun 202691 flights95.6%

Scale runs 65% to 100%. Rows with fewer than 30 flights show a dash.

By weekday, F9 1500 did best on Thursday at 93.5% on time and worst on Sunday at 79.5%. Each day rests on about 46 flights, so a gap of 14 points is worth noticing but could still narrow in another year.

Delay causes

Why F9 1500 runs late

One category carries most of the weight here. Late-arriving aircraft accounts for 46% of the 3,384 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.

Late-arriving aircraft
46%
National Airspace System
31%
Carrier
22%
Extreme weather
1%

46% 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 3,384 reported delay minutes here, that single category outweighs weather by 43 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 3,384 delay minutes reported on F9 1500.

Cancellations are rare at 0.62%, 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

5.3% 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 a little over an hour, which a normal layover absorbs.

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. 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 320 flights under F9 1500 in the data flew ONT 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. 320 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 1500

For a booking, F9 1500 has one of the better records a US domestic flight can show: 86.2% on time and 0.62% cancelled. That is a base rate, not a promise about any single day.

Where to go next

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.

Key figures