About 1 in 9 DL 1221 flights from Milwaukee arrived 15+ minutes late, diverted or cancelled over the past year (11%); 1.4% were cancelled. The typical flight landed 15 minutes early.
DL 1221: MKE → ATL
Scheduled to leave Milwaukee at 5:45 a.m. local time. Over the past year it arrived on time 89% of the time (365 flights), in line with other DL flights on the route at that hour (89%). Last seen in the data Aug 31, 2026.
Month by month
By day of week
| Day | Flights | On time |
|---|---|---|
| Monday | 53 | 87% |
| Tuesday | 52 | 87% |
| Wednesday | 52 | 88% |
| Thursday | 52 | 94% |
| Friday | 52 | 90% |
| Saturday | 52 | 92% |
| Sunday | 52 | 85% |
Why it was late
All flights MKE → ATL · Connecting off DL 1221? Check the risk
Questions
How often is DL 1221 from MKE to ATL late?
Delta Air Lines 1221 from Milwaukee, WI to Atlanta, GA arrived 15 or more minutes late, was diverted or was cancelled on 11% of 365 scheduled flights between September 2025 and August 2026. 1.4% 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 Delta Air Lines for today's flight. Method.