BUSINESS BRIEFING / TRAVEL

Delta Air Lines Inc., American Airlines and United Airlines raised most U.S. fares by as much as $20 for a round trip, the second increase in as many weeks, as they try to take advantage of peak summer travel demand.

AMR Corp.’s American boosted most route prices by $10 to $20 Wednesday, and Delta, UAL Corp.’s United and Continental Airlines Inc. matched those fares, FareCompare.com said. Delta and Southwest Airlines Co. led carriers in a $20 round-trip increase earlier this month.

Two successful fare increases in a month would support an industry report that the slump in global airline travel may have reached a “floor” after a 9.3% decline in passenger traffic last month. Airlines slashed prices to win sales in the recession.