Sleeping at an airport overnight, once almost a sport for the young and short of cash, has become a lot more common lately, affecting even older and professional travelers. And a big reason is that airlines are no longer as free with complimentary hotel vouchers as they once were.

“Belt tightening by airlines over the last 18 months, and more so this year,” is how Randy Petersen, editor of the online magazine InsideFlyer and the frequent-flier Web site FlyerTalk.com, explains it.