A U.S. government investigation found no evidence of airline price-gouging after the deadly May 2015 Amtrak crash in Philadelphia that snarled rail travel for days. "There was no evidence of unfair manipulation of airfares or capacity, nor evidence of unconscionable increases in fares beyond normal pricing levels," the U.S. Transportation Department said in a letter to five airlines, American, Delta, JetBlue, United, and Southwest.

"We are gratified by the decision and we were confident there would be no finding of wrongdoing by American," the airline said. American operates a hub and more than 400 daily flights in Philadelphia.