In January, Midway Airport was the worst in the nation for on-time departures.
The latest report from the Bureau of Transportation shows Baltimore's airport has taken over the last spot.
In February, Midway rose up to number 20 out of the nation's 29 major airports with 70 percent of flights departing on time.
O'Hare improved moving from 26th to 15th with nearly 74 percent of flights on time.
For arrivals, Midway ranked 9th with 78 percent of flights on time. O'Hare ranked 15th with 73 percent of its flights on time.