Delta Air Lines Inc is likely to increase capacity this summer by adding flights in June and July as U.S. domestic travel slowly picks up amid the novel coronavirus pandemic, its chief executive officer said on Wednesday.

CEO Edward Bastian told Fox Business Network the airline's 60% cap on passenger load would help it maintain social distancing, while it also undertakes other efforts such as cleaning to boost customer confidence.

"Today our load factor on Delta is somewhere about 35-40% full," he said in an interview. "Once we get close to 60% on an individual route that'll be the trigger for us to add more planes into the system."

Bastian said he expected to add about 200 flights in June, and probably another 200 or 300 flights in July.

Overall, U.S. travel continues to be "slow," he said, adding that he expects it to recover in the next 12 to 18 months, although international travel may not restart more fully until 2021.

He said he expects the company's costs to be down more than 50% in the second quarter on year-over-year basis, and that with the help of U.S. government assistance he sees ending June with a $14 billion cash balance to help the airline ride out the pandemic.

Sources familiar with the airline's strategy had told Reuters Delta's plan to limit passengers to 60% of its seats was key to its efforts to manage fallout from the coronavirus outbreak.