Delta Air Lines Inc. is taking social distancing beyond keeping some middle seats off limits, saying it will cap sales at 50% in first class and at 60% in economy sections.

Delta will block select window and aisle seats in the coming weeks for aircraft with 1-by-2, 2-by-2 and 2-by-3 seating configurations, the Atlanta-based carrier said Tuesday. It began keeping middle seats from sale on all flights in mid-April, excluding first class. The changes announced Tuesday, which expand distancing measures to Delta’s full fleet of mainline and regional aircraft, will remain in place through June.

Airlines are revamping seating, boarding, aircraft cleaning and other routine practices in an effort to slow the spread of the new coronavirus and reassure consumers that it’s safe to fly. A drop in passenger traffic of about 95% from a year ago has left many planes with plenty of empty seats.

Read more: Dreaded Middle Seat Is Gone, for Now, in Name of Distancing

American Airlines Group Inc. has said it won’t assign 50% of the middle seats on its planes unless necessary, while United Airlines Holdings Inc. is blocking middle seats in all its cabins. Frontier Airlines Holdings Inc. on Monday said it would charge as much as $89 extra for passengers who want to book a spot next to an empty middle seat.