On October 27, northern airlines will switch to winter schedules based on IATA slot seasons. They will operate their winter plan until March 29, the day before they switch to summer schedules. 
Delta Air Lines is no exception.
On October 27, northern airlines will switch to winter schedules based on IATA slot seasons. They will operate their winter plan until March 29, the day before they switch to summer schedules. Delta Air Lines is no exception.