MEMPHIS, Tennessee (CNN) -- A Florida man who was arrested on charges of carrying a loaded gun in his carry-on luggage was on a one-day round trip to Memphis apparently trying to beef up his frequent-flier mileage, according to the FBI.

Barry Brunstein, 55, was charged Friday with attempting to board an aircraft with a firearm and released on $5,000 bond, said Steve Anthony, a spokesman for the FBI in Memphis.

Since Brunstein had not planned to leave the airport, "it's very possible" that frequent-flier miles were the motivation for the trip, Anthony said.

The Florida resident boarded a Delta flight Friday morning in Tampa and flew to Atlanta, Georgia, where he switched planes without leaving the secure area of the airport and flew on to Memphis International Airport, Anthony said.

Brunstein had intended to turn around, again without leaving the secure area of the airport, and take a return flight to Tampa, according to the FBI. But his plans fell apart when a random check at the departure gate in Memphis turned up a loaded Beretta 9 mm semiautomatic pistol in his carry-on luggage, Anthony said.

The pistol is the standard Army sidearm that law enforcement personnel often use. It has a 15-round magazine.

The passenger acknowledged it was his, Anthony added. "You just don't know what was in his mind," he said.

The incident appears to have had nothing to do with any planned terror act nor is there any indication it was related to the September 11 terror attacks.

"Before 9-11, this kind of thing would happen every so often; now it has become big news," Anthony said. "The government would probably be trying to have him held without bond if there was a thought there was more to it."

Brunstein is scheduled to return to Memphis for a hearing in January.

As a result of the decline in passengers in the wake of the terror attacks, Delta Air Lines has extended the eligibility period for miles through March. Delta awards 2,000 frequent-flier miles for a round trip, plus a number of extra miles, depending on a passenger's elite-level status, a ticket agent said.

A spokeswoman for Delta Air Lines would not comment. "I don't have any information to share on this because it is related to a security matter," said Janis Logue.

"We're in the process of trying to check up on it," said Lt. Robert Dixon of the Tampa Airport Police Department, who said he found out about the apparent breach of security from a news agency. "We didn't know a thing."

Though the man was carrying a Florida concealed firearms permit, "that will do him no good on an airplane," Dixon said. "If he's on an aircraft with a gun, somebody screwed up somewhere. The screening responsibility rests with the airline; it's not a law enforcement function."

Brunstein did not return a message left on his answering machine.