Flight Reliability
DL 3520 · Delta Air Lines
Salt Lake City → Colorado Springs (SLC–COS)92% of its flights flew this route. The rest (FSD–MSP, MSP–FSD) are included in these numbers.
- 92%
- Arrive within 15 minutes
- 3 min early
- Average arrival delay
- 0.5%
- Cancelled
- 8 min early
- Median arrival delay
Based on 213 historical flights. Data through May 2026.
What the data says
Thursdays have been rough.
DL 3520 arrived on time 97% of the time on Fridays and just 80% on Thursdays. That gap is worth planning around.
Better than the Delta Air Lines network average.
DL 3520 arrived on time 92% of the time, versus 81% across the Delta Air Lines network.
Trending in the right direction.
DL 3520 arrived on time 94% of the time over the last three months in the data, compared with 87% in the three months before that.
The breakdown
- Mon93%(30 flights)
- Tue93%(29 flights)
- Wed93%(29 flights)
- Thu80%(30 flights)
- Fri97%(30 flights)
- Sat90%(31 flights)
- Sun94%(32 flights)
- 9 AM–12 PM—(7 flights)
- 12–3 PM—(9 flights)
- 3–6 PM—(7 flights)
- 6–9 PM91%(188 flights)
Jun 97% → Dec 89% on time
| Month | On-time percentage | Flights |
|---|---|---|
| June 2025 | 97% | 37 |
| July 2025 | 74% | 31 |
| August 2025 | 90% | 30 |
| September 2025 | 97% | 30 |
| October 2025 | 97% | 31 |
| November 2025 | 97% | 30 |
| December 2025 | 89% | 18 |
- Departures on time
- 91%
- Diverted
- 0.5%
- Flights flown
- 211
- Months covered
- 9
Same route, other flights
Keep nerding
Based on 213 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.