Following announcements by American and United airlines, more travelers now can check-in for flights using mobile devices and obtain paperless boarding passes

. United began offering the option for flights departing from its hubs, as well as Las Vegas, Dallas Fort Worth and New York LaGuardia, and expects to include a total of 30 markets "by summer." AA expanded its existing program to 19 additional airports, including Houston Intercontinental, New York LaGuardia, Orlando, Phoenix, San Francisco and Washington Dulles, and said more would be added "in the coming months."