(Updates throughout with FBI confirmation, details from affidavit, changes last name of suspect based on updated FBI spelling) MEMPHIS, Tenn., Dec 29 (Reuters) - A Florida man arrested in the Memphis, Tennessee, airport for allegedly carrying a loaded gun in his carry-on luggage after apparently boarding flights in two other cities was free on bond on Saturday, the FBI said. Barry Brunstein of Tampa was charged on Friday with attempting to board an aircraft with a concealed weapon, an FBI spokesman said. He was released later on $5,000 bond. Brunstein had taken a Delta Air Lines Inc. (DAL) flight Friday from Tampa to Atlanta. He then switched to another Delta flight and continued to Memphis, according to the FBI. Brunstein was preparing to board a return flight to Atlanta when security at the Memphis airport chose him for a random search, according to an FBI affidavit filed in federal court. Many airports have adopted such security measures following the Sept. 11 attacks on the United States by men who hijacked commercial aircraft and crashed them into New York's World Trade Center and the Pentagon outside Washington. The hand search turned up a 9mm Beretta semi-automatic pistol in Brunstein's carry-on baggage, the affidavit said. The pistol had 12 bullets in its magazine and one in the chamber. The affidavit said Brunstein acknowledged the gun was his. Although it didn't say he had the gun in his possession when he boarded the first flight, a federal official who didn't want to be named told Reuters the gun went through security in Tampa. The official also said Brunstein did not have to go through a security checkpoint in Memphis before the random search, because he never left the gate area. Brunstein may have taken the flights in order to build up frequent flier miles and improve his frequent flier benefits level, the official said. It was not clear whether he passed through a security checkpoint when he changed planes in Atlanta. FBI supervisory special agent Steve Anthony declined to comment on the reason for Brunstein's trip. "The investigation is continuing to determine what exactly his plans were," he said. Due to a typographical error, Brunstein had been identified as "Burnstein" in the affidavit, Anthony said. A spokeswoman for Atlanta-based Delta declined comment. "We don't comment on security matters," she said. Brunstein is scheduled for a court hearing on Jan. 17 in Memphis. ©2001 Reuters Limited.