Delta Air Lines Inc. boosted the number of flights it will restore to service in June and July to allow for spacing among passengers as demand increases.

“Once we get close to 60 per cent on an individual route, that’ll be the trigger for us to add more planes into the system,” Chief Executive Officer Ed Bastian said Wednesday on Fox Business News.

The carrier will add 200 flights in June and may add as many as 300 in July, he said. Just two days earlier, the airline said it planned to add 100 flights next month.

The airline’s plan to beef up its schedule bolsters reports from other carriers seeing moderate growth in demand that had been nearly wiped out by the coronavirus pandemic. Those encouraging signals have been tempered by warnings that the outlook remains uncertain and that a full recovery could be lengthy, especially on international routes.

Also Wednesday, Scott Kirby, on his first day as CEO of United Airlines Holdings Inc., said on CNBC that the carrier is increasing the size of planes on 30 to 40 flights a day to promote physical distancing as its number of passengers rises to as many as 40,000 a day from 10,000 in April.

Delta, which has pledged to sell no more than 60 per cent of the seats on each plane, had slashed daily flights to 1,000 and grounded about 650 planes.

Its portion of seats filled per plane has risen to between 35 per cent and 45%, in part because it has reduced flights, Bastian said. The Atlanta-based carrier earlier this week said it would restore some flights to Europe, China and the Caribbean next month, along with some domestic routes.