About 1 in 6 DL 1240 flights from Atlanta arrived 15+ minutes late, diverted or cancelled over the past year (18%); 0.3% were cancelled. The typical flight landed 4 minutes early.
DL 1240: ATL → DTW
Scheduled to leave Atlanta at 11:00 a.m. local time. Over the past year it arrived on time 82% of the time (365 flights), in line with other DL flights on the route at that hour (83%). Last seen in the data Aug 31, 2026.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 53 | 87% |
| Tuesday | 52 | 79% |
| Wednesday | 52 | 88% |
| Thursday | 52 | 81% |
| Friday | 52 | 85% |
| Saturday | 52 | 81% |
| Sunday | 52 | 77% |
Why it was late
All flights ATL → DTW · Connecting off DL 1240? Check the risk
Questions
How often is DL 1240 from ATL to DTW late?
Delta Air Lines 1240 from Atlanta, GA to Detroit, MI arrived 15 or more minutes late, was diverted or was cancelled on 18% of 365 scheduled flights between September 2025 and August 2026. 0.3% 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 Delta Air Lines for today's flight. Method.