Police identified the suspect as Sarawut Thepsila, 35. He was apprehended by airport security officials after parking the stolen bus in an area where parking was prohibited and quarreling with airport officials at Gate 10 at about 11pm, they said.
He told airport security that he was waiting to pick up diplomats from a country he did not identify. He was unable to provide details of the flight they were arriving on, police said.
Airport security subsequently handed him over to police.
Earlier Friday night, members of the Support Services Department of the Royal Thai Armed Forces, filed a complaint at Romklao police station saying a Hino bus that had been parked inside a military housing compound in Lat Krabang district had disappeared.
Police reviewed security camera footage in the area and found that the bus had been driven out of the compound around noon on Friday.
Sarawut told police that while he walked past the bus he saw its door was open and its keys were near the driver’s seat. He interpreted this as an invitation to drive it away.
His first destination was Don Mueng International Airport, police said. He subsequently drove the bus to Suvarnabhumi International Airport to pick up the unknown diplomats, police said.
Police said the suspect was previously arrested on drug-related charges six times.