* Passengers on international flights to reach record
* Carriers as a whole swung to profit in first quarter
May 15 (Reuters) - The number of people flying on U.S. airlines will rise this summer, aided by a record level of international travelers, an industry group said on Thursday.
Airlines for America, a lobbying association for U.S. airlines, forecasts that about 210 million passengers will fly on the nation's carriers between June and August, up 1.5 percent from last year.
The outlook includes 29.9 million passengers on international flights, the highest level ever, the group added. The top nonstop destinations from the United States were Canada, Mexico, United Kingdom, Germany and Japan, based on flight schedules.
Travel by air "remains one of the best consumer bargains in America, given its superior speed and affordability," John Heimlich, chief economist at Airlines for America, said in a statement.
Summer is a seasonally strong period for airlines as leisure travel picks up.
The group also said lower fuel costs helped U.S. carriers improve their performance in the first quarter as a group even as winter storms forced the cancellation of thousands of flights. Nine publicly traded U.S. airlines collectively had a profit of $401 million in the period, compared with a loss of $552 million a year earlier, Airlines for America said.
Carriers have cited healthy demand heading into the warmer months. Delta Air Lines Inc said last week that unit revenue, an important airline measure, could rise as much as 7 percent in both May and June. Southwest Airlines Co said on Wednesday that second quarter bookings appeared strong. (Reporting by Karen Jacobs in Atlanta; Editing by Lisa Shumaker)