Like JetBlue and Southwest, Delta currently is blocking middle seats in their 3+3 seat configurations. Now, DL is stating that they will continue to block middle seats at least until 01/06/2021.
https://www.usatoday.com/story/trav...jan-6-coronavirus-pandemic-safety/5615602002/
https://www.usatoday.com/story/trav...jan-6-coronavirus-pandemic-safety/5615602002/