About 1 in 5 F9 3978 flights from Las Vegas arrived 15+ minutes late, diverted or cancelled over the past year (22%); 2.4% were cancelled. The typical flight landed 8 minutes early.
F9 3978: LAS → DFW
Scheduled to leave Las Vegas at 6:00 a.m. local time. Over the past year it arrived on time 78% of the time (255 flights), in line with other F9 flights on the route at that hour (81%). Last seen in the data Aug 31, 2026.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 40 | 78% |
| Tuesday | 25 | 80% |
| Wednesday | 26 | 85% |
| Thursday | 41 | 83% |
| Friday | 47 | 85% |
| Saturday | 33 | 73% |
| Sunday | 43 | 67% |
Why it was late
All flights LAS → DFW · Connecting off F9 3978? Check the risk
Questions
How often is F9 3978 from LAS to DFW late?
Frontier Airlines 3978 from Las Vegas, NV to Dallas/Fort Worth, TX arrived 15 or more minutes late, was diverted or was cancelled on 22% of 255 scheduled flights between September 2025 and August 2026. 2.4% were cancelled.
Flight numbers change. Figures cover flights with this airline, number and route only. "Likely range" is the 95% interval for the true on-time rate given the number of flights. This is history, not live status: check Frontier Airlines for today's flight. Method.