Southwest Airlines raised prices this week, prompting other U.S. carriers to follow suit, pushing prices up 4.5 percent on the year, a fare expert said. Rick Seaney at FareCompare said fares were up 4.5 percent on the year after Southwest instigated a price hike that was an oddity -- a discount airline raising prices after another airline had prices rolled back due to a lack of support from other carriers. The Dallas Morning News reported Tuesday United Airlines tried raising prices last week but found only Delta Air Lines followed suit. United then rolled prices back only to have Southwest, a discount carrier, raise prices a week later. Southwest raised prices between $4 and $10 per round trip, the newspaper said. After it did so, many others raised their prices as well. \"In almost a decade, we have never seen a domestic airfare hike that was quickly rolled back only to be resurrected by a low-cost airline,\" Seaney said, writing about United Airlines in an online posting. FareCompare said airlines made 14 attempts to raise prices this year, but half those attempts were rolled back when one or two carriers found themselves alone in the effort to raise prices in the competitive industry.