United Airlines raised U.S. domestic airfares by "as much as $30 roundtrip ... across its entire route system

," according to FareCompare's Rick Seaney. Should it stick, this latest fare hike would mean "that many travelers will be paying up to $130 more than they did in the first week of January 2008 for domestic airline tickets," Seaney reported, adding that prices are "likely to continue an upward spike in the coming weeks."