The Birmingham-Shuttlesworth International Airport in Alabama was evacuated for over two hours on Sunday while police investigated a bomb threat that turned out to be a false alarm, police said.
"It ended up being nothing," said Birmingham Police Sergeant Johnny Williams.
The terminal was evacuated at about 4 p.m. CST (5 p.m. EST), after an employee found a note in a bathroom saying that a bomb had been placed in the terminal, Williams said.
Police searched the building with bomb-sniffing dogs and conducted a sweep of the entire facility but found no threat, he said.
The airport was in the process of reopening while police were still examining the note, Williams said.
Several arriving flights were diverted to an airport in Huntsville, Alabama, while more than a dozen outbound flights were delayed, the airport's website showed.
The incident comes two days after a gunman killed a Transportation Security Administration agent and wounded several other people at Los Angeles International Airport.