Flight Reliability
DL 4039 · Delta Air Lines
Seattle → Bozeman (SEA–BZN)98% of its flights flew this route. The rest (MSP–RIC) are included in these numbers.
91
Nerd Approved
WanderNerd Reliability Score
- 85%
- Arrive within 15 minutes
- 2 min early
- Average arrival delay
- 0.6%
- Cancelled
- 12 min early
- Median arrival delay
Based on 167 historical flights. Data through May 2026.
What the data says
Sunday scaries are real for this one.
DL 4039 arrived on time 96% of the time on Saturdays and just 68% on Sundays. That gap is worth planning around.
A bit ahead of the Delta Air Lines network.
DL 4039 arrived on time 85% of the time, versus 81% across the Delta Air Lines network.
The breakdown
- Mon92%(25 flights)
- Tue84%(25 flights)
- Wed91%(22 flights)
- Thu82%(22 flights)
- Fri82%(22 flights)
- Sat96%(25 flights)
- Sun68%(25 flights)
- 12–3 PM—(3 flights)
- 3–6 PM—(5 flights)
- 6–9 PM84%(158 flights)
63%
May
Jan 93% → May 63% on time
| Month | On-time percentage | Flights |
|---|---|---|
| January 2026 | 93% | 30 |
| February 2026 | 86% | 28 |
| March 2026 | 87% | 30 |
| April 2026 | 90% | 30 |
| May 2026 | 63% | 30 |
- Departures on time
- 86%
- Diverted
- 0%
- Flights flown
- 166
- Months covered
- 9
Same route, other flights
Keep nerding
Based on 167 historical flights, because apparently we checked. Historical flight data: U.S. Bureau of Transportation Statistics, June 2025 – May 2026. Data through May 2026. How we calculate this.