U.S. airlines and agencies are preparing for increased domestic air travel this summer even as the government continues to debate whether to allow more foreign travelers to visit.

Shares in American Airlines (AAL.O), United Airlines (UAL.O) and Delta Air Lines (DAL.N) were sharply higher on Tuesday after top executives said that the pace of a leisure travel recovery was increasing.

"We've been very, very pleased with the pace of demand recovery," Delta President Glen Hauenstein told an industry conference. "Bookings have been better than expected."

As more Americans pass through airports, the Transportation Security Administration (TSA) plans to hire another 1,000 officers by July 4, a peak U.S. travel period, after hiring 3,000 officers since Jan 1.