(CNN) -- A U.S. Airways flight on its way to Dallas returned to Philadelphia on Thursday for security reasons, the Federal Aviation Administration said.
One man is in custody after authorities were informed of a Facebook posting that suggested a passenger on the plane may have had explosives, FBI spokesman JJ Klaver said.
The suspect in custody was a passenger.
"The person may have been targeted as a hoax," Klaver said. "This is still being investigated."
Flight 1267 landed at Philadelphia International Airport, and authorities began a security check while passengers remained on the plane, airline spokesman Davien Anderson said.
The FBI has taken over the investigation, a spokeswoman for the Philadelphia airport said.
Authorities say the Airbus A319 -- which was carrying 69 passengers -- has since been cleared after all passengers were removed.