The plane intruder, identified as Sutthidej Mahapan, 39, was summoned to Khlong Hoi Kong police station for further questioning on Tuesday, after the incident created widespread criticism over the lack of security by both the airport and the airline.
He was accompanied to the police interview by his family members, Thai Rath online reported.
Police earlier accompanied Mr Sutthidej to a medical examination at Hatyai Hospital, suspecting psychiatric problems. He told doctors he could not remember events, including Saturday’s incident at the airport.
He could not respond to questions correctly, police added.
The family insisted Mr Sutthidej was mentally ill but not a threat to anyone. He underwent treatment at Songkhla Rajanakarindra Psychiatric Hospital in 2009 and took medicine for two years before the treatment was suspended because the family could not afford travelling and medical expenses.
Family members said they were told by Mr Sutthidej that he wanted to take a bus to a Tesco Lotus superstore for an outing, but he rode the bus until the airport, its last stop. He went in because he saw many people.
A medical team at Hatyai Hospital prescribed medicine for Mr Sutthidej and instructed his family to watch him closely and ensure that he takes the medication continuously.