The incident, which was first reported around 8:30 a.m., prompted airport police to shut down the entrance to the airport.
A bomb squad was called to the scene to investigate. Authorities found a replica rifle and replica grenades, which were deemed inert. Police said the man, described as a "World War II enthusiast," was there to pick someone up from the airport.
All roads were eventually reopened.
All Traffic Lanes have been opened into the Airport. Police Activity has been concluded.— LA Airport PD (@LAAirportPD) August 17, 2018
Some travelers stuck in traffic were seen running from their vehicles toward the terminal in a bid to make their flights.
Traffic remained heavy in the area after the incident.