DALLAS (AP) — If you’re buying an airline ticket soon, get ready to pay a few bucks more.

According to fare trackers, JetBlue Airways and Southwest Airlines are leading a round of price increases that will boost the base fare on many medium-length and long flights by $10 per round trip.

United, Delta, American and US Airways said Thursday that they had matched the increases.

J.P. Morgan analyst Jamie Baker, who tracks fares, said United and US Airways expanded the price increases to routes that Southwest doesn’t fly and included Denver, where Southwest had not raised prices. Rick Seaney, CEO of FareCompare.com, said Thursday that all the largest U.S. airlines had raised fares.

Baker and Seaney said Jet- Blue took price increases that other airlines limited to a few markets such as Florida and expanded them nationwide last week. Southwest jumped in on Wednesday, they said.

JetBlue did not immediately respond to a request for comment. Southwest spokeswoman Ashley Dillon said her airline raised prices to match JetBlue and “ cover operating costs including the high price of jet fuel.”

Jet fuel accounts for about one-third of an airline’s costs — about the same as labor — and the bill has been rising along with crude oil prices. This week, the spot price for Gulf Coast jet fuel was 12.1 percent higher than a year ago and up 8.5 percent so far in 2012, according to the U.S. Energy Information Administration. That could mean more fare hikes ahead.

“It is pretty clear airlines will continue to try to recoup fuel increases regularly this year, with passengers telling carriers exactly when the price of middle seats has stepped over the line,” said Seaney.

Airlines raised base fares about a dozen times in 2011. But at the same time, they sacrificed revenue by simultaneously running sales to fill seats during slower travel periods or in specific markets. This week, even as it raised base fares, American launched a sale on Miami flights. Many consumers are savvy enough to wait for sales before buying tickets.