TRAVIS AIR FORCE BASE, Calif. (AP) — The U.S. Air Force airman who was injured when he and two childhood friends tackled a heavily armed gunman on a Paris-bound train is back in his native California.Airman 1st Class Spencer Stone arrived at about 8:30 p.m. Thursday night at Travis Air Force Base in Fairfield, California, near Sacramento.Stone stepped off the plane from Rammstein, Germany, to cheers from about 200 people who had gathered to greet him.