Delta Air Lines is capping seating at 50 percent of capacity for First Class and 60 percent on economy and premium economy cabins through June 30. The move means that middle seats will remain blocked along with some window and aisle seats on aircraft with 1x3, 2x3 and 2x3 seating configurations. Blocked seats will be shown as unavailable when booking, and people traveling together who wish to sit in adjacent seats can arrange that with a gate agent.