United Airlines Holdings (NASDAQ:UAL) and Delta Air Lines (NYSE:DAL) are both planning to add back parts of their international schedules while shifting domestic capacity as the COVID-19 pandemic continues to weigh on global travel demand.

United said Friday it intends to resume service on nearly 30 international routes in September, including launching new service between Chicago and Tel Aviv and restoring service to markets including Munich, Sydney, Frankfurt, and Mumbai. Delta, meanwhile, said it plans to resume flights between Atlanta and Tokyo, Munich, Sao Paulo, and Dublin.

A United 787 in flight.

Image source: United Airlines Holdings.

Airlines have been hit hard by the pandemic, with second quarter revenue falling more than 80% year over year due to lack of demand. The companies have been slowly rebuilding their domestic schedules as stay-at-home orders are lifted, but an uptick in new COVID-19 cases has put a damper on the recovery.

Delta said it will add about 700 flights in August, down from previous plans to add about 1,000. United will fly 37% of last year's schedule in September, including about 40% of its domestic schedule.

Most of the demand airlines are seeing right now is coming from leisure travel, which is likely to fall off when summer ends. Airlines are currently prohibited from doing layoffs as a condition for receiving government assistance earlier in the year, but those restrictions end on Sept. 30 and the industry is expected to conduct significant layoffs starting in October.

United warned earlier this week it might need deep cuts to its pilot ranks absent additional government assistance or union concessions, while Delta has floated the idea of cuts to minimum pay as a way to avoid layoffs.