DALLAS — Major U.S. airlines are raising the price of some tickets favored by business travelers again, this time by up to $120 per round trip. Fare experts said Delta started the latest increase on Monday, which was matched immediately by American and a day later by United, Continental and US Airways. It’s the second big increase in fares in as many weeks. The airlines’ fuel prices have risen 50 percent over the past year. They eliminated many flights when they were losing money in 2008 and 2009, which has given them the power to raise fares now that planes are more crowded and travel demand is rebounding.

JP Morgan analyst Jamie Baker said it made sense for the big airlines to target corporate travelers, who are considered less sensitive to price increases. He said airlines may have raised vacation fares as high as they can without causing a loss of revenue — presumably by driving away budget-conscious customers.