U.S. airlines surged as JPMorgan Chase & Co. said carriers were raising domestic fares for the second time in five weeks.

American Airlines Group Inc. boosted ticket prices by US$5 on one-way U.S. flights on Wednesday, said JPMorgan Chase analyst Jamie Baker, who tracks fares. The move was followed by Southwest Airlines Co., the biggest domestic carrier, and Hawaiian Holdings Inc.

Airlines are attempting to push through the new price increase more quickly than expected after lifting fares in the second week of May, Baker said. The industry is benefiting from strong demand while the supply of flights and seats is crimped by the grounding of Boeing Co.'s 737 Max.

"We were obsessing over domestic fares much less than usual, given what we viewed as a low probability of further increases," Baker said. "We are pleased that our skepticism was proven ill-placed."

American jumped 5.8% to US$32.91 at 11:04 a.m. in New York, the biggest gain on the S&P 500 Index. Southwest and United Continental Holdings Inc. also ranked among the 10 best performers on the stock gauge.

Southwest has also instituted smaller increases over the last month, "leaving several thousand fares as much as US$15 one-way higher than this time last month," Baker said.

American and Southwest this week removed the Max from their schedules through the U.S. Labor Day holiday in early September, extending the planned hiatus from August.