A list of aircraft operators that have that have suffered an accident, serious incident or hijacking. The list may also contain defunct airlines or airlines that in the meantime have changed their name or have merged.

Airlines:
Bangkok Airways
One-Two-Go Airlines
Pacific Overseas Airlines (merged with Siamese Airways into Thai Airways, 1951)
Phuket Airlines
Sahakol Air
Siamese Airways (merged with Pacific Overseas Airlines into Thai Airways, 1951)
Thai Airways (merged into Thai Airways International in 1988)
Thai Airways International

Flying schools, Aeroclubs, Paraclubs:
Siam Air Sports

Government:
Royal Thai Border Police
Thai Government

Military:
Royal Thai Air Force - RTAF
Royal Thai Navy