Flight number record
F9 3978
Frontier Airlines · Las Vegas to Dallas-Fort Worth
- Route
- LAS → DFW
- Departs
- 06:00
- Flights
- 255
- Period
- September 2025 to August 2026
Historical statistics for September 2025 to August 2026, not live status. For today’s F9 3978, check with Frontier Airlines.
F9 3978 lands a B, 3 points better than the national rate of 77.3%. About one flight in five arrives 15 minutes late or worse, and those flights are late by about an hour on average. That rests on 255 flights, with a median arrival 9 minutes early.
Key figures
On time
80.6%
Arrivals under 15 minutes late, of 248 completed flights
Avg delay
65 min
Across delayed arrivals only, not all flights
Cancelled
2.35%
National rate is 1.89%
1 hour+ late
4.4%
National rate is 8.3%
These figures cover 255 flights between September 2025 and August 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.
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Schedule
When F9 3978 flies
F9 3978 flies LAS to DFW without a single fixed slot. Its most common scheduled departure was 06:00, used on 74 of 255 flights.
- Departs 06:0074 flights29.0%
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 06:00 departure sits in the 5am–8am window. Across every US flight scheduled in that window the on-time rate is 89.3%, and F9 3978 runs 9 points worse at 80.6%. Early departures usually start with an aircraft that has not flown yet that day, which is most of why the window does well.
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Against the route
F9 3978 next to LAS to DFW
Every carrier on LAS to DFW combined arrived on time 79.9% of the time across 5,142 flights, so F9 3978 is about level with it. Frontier flew 878 flights on the same city pair under all its flight numbers, including this one, and those ran 77.8% on time. Across its whole network Frontier Airlines managed 72.7%, which this flight beats by 8 points.
| Compared with | Flights | On time | Avg delay | Cancelled | Grade |
|---|---|---|---|---|---|
| F9 3978thin sample | 255 | 80.6% | 65 min | 2.35% | B |
| All Frontier Airlines on LAS–DFW | 878 | 77.8% | 78 min | 1.94% | B |
| All carriers on LAS–DFW | 5,142 | 79.9% | 97 min | 2.49% | B |
| Frontier Airlines, whole network | 213,022 | 72.7% | 84 min | 2.05% | C |
Across the year
F9 3978 quarter by quarter
Quarter by quarter F9 3978 held fairly steady: 76.4% in Oct–Dec 2025, 86.3% in Jan–Mar 2026, 78.7% in Apr–Jun 2026 and 81.4% in Jul–Sep 2026. A spread of 10 points is about what a sample of this size moves on its own, so the annual figure is a fair summary.
- Jul–Sep 202514 flights—
- Oct–Dec 202557 flights76.4%
- Jan–Mar 202677 flights86.3%
- Apr–Jun 202647 flights78.7%
- Jul–Sep 202660 flights81.4%
Scale runs 70% to 90%. Rows with fewer than 30 flights show a dash.
By weekday, F9 3978 did best on Friday at 88.9% on time and worst on Sunday at 72.5%. Each day rests on about 36 flights, so a gap of 16 points is worth noticing but could still narrow in another year.
Arrival by arrival
How late F9 3978 runs when it is late
F9 3978 often beats the schedule: 82 of 248 completed flights, 33%, arrived 15 minutes or more early. The 48 late arrivals split 15 under half an hour, 22 between 30 and 60 minutes, and 11 an hour or more.
- 15+ min early82 flights33.1%
- Within 15 min118 flights47.6%
- 15–29 min late15 flights6.0%
- 30–59 min late22 flights8.9%
- 1–2 hours late4 flights1.6%
- 2+ hours late7 flights2.8%
Scale runs 0% to 100%.
Share of 248 completed flights by arrival against schedule.
9 of 38 late departures made up the time and arrived on time, 24% of them. In the other direction, 19 flights left on time yet arrived 15 minutes late or more, so that delay built up after pushback: in the air, in a holding pattern or on the ground at DFW.
The worst days
Worst days for F9 3978
The latest arrival of the period was on 5 September 2025, 8 hours 56 minutes behind schedule; most of its delay minutes were filed as a late-arriving aircraft. Three of the five worst days fell in November 2025.
| Date | Arrived late by | Largest filed cause |
|---|---|---|
| 5 September 2025 | 8 hours 56 minutes | Late-arriving aircraft |
| 20 November 2025 | 4 hours 14 minutes | Late-arriving aircraft |
| 26 November 2025 | 3 hours 34 minutes | Late-arriving aircraft |
| 24 November 2025 | 2 hours 50 minutes | Late-arriving aircraft |
| 13 April 2026 | 2 hours 36 minutes | Carrier |
Delay causes
Why F9 3978 runs late
Carriers report a reason for every delay minute they cause, in five DOT categories. The split below is by minutes, not by number of flights, so a handful of very long weather delays weighs as much as many short ones. It covers 3,138 reported delay minutes.
- 41%Late-arriving aircraft
- 31%Carrier
- 25%National Airspace System
- 2%Extreme weather
41% of delay minutes trace back to a late-arriving aircraft, meaning the plane was already behind before it got here. Across 3,138 reported delay minutes here, that single category outweighs weather by 17 to one. The split is drawn from 3,138 delay minutes reported on F9 3978.
Cancellations sit at 2.35% against a national 1.89%, which is ordinary. Diversions add another 0.39%.
Connections and routes
What a delay on this flight costs
Badly late arrivals are rare here: only 4.4% land an hour or more behind schedule, against 8.3% nationally. Connections built on this flight are about as safe as US domestic connections get, though a cancelled flight still ignores every layover you give it.
The 1,055 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 255 flights under F9 3978 in the data flew LAS to DFW. 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. 255 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 3978
For a booking, read F9 3978 as 80.6% on time with 2.35% cancelled over 255 flights. Those are rates from the past twelve months, not a forecast for any particular day.
Related
Where to go next
- LAS to DFW, every carrier and departure
- DFW to LAS, the return direction
- American Airlines 777 on the same route70.1%
- Frontier Airlines 1650 on the same route75.5%
- American Airlines 1908 on the same route88.3%
- American Airlines 1584 on the same route85.7%
- American Airlines 2932 on the same route94.1%
- Harry Reid International (LAS) delay statistics
- Dallas/Fort Worth International (DFW) 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.