National Aviation Day is observed in Thailand every January 13 to commemorate the first demonstration flight open to the public, which took place in 1914. The day marks the anniversary of this flight, attended by King Vajiravudh, and is considered the birthday of Thai aviation. The history of aviation in Thailand began with the establishment of the Royal Siamese Air Force in 1913 and the first public exhibition flight at the Royal Bangkok Sports Club. National Aviation Day was officially established in 1994 and celebrated for the first time in 1995. It is an official observance regulated by the Thai government, although it is not a public holiday. Notable locations associated with Thai aviation include Don Mueang International Airport, which is the oldest operating airport in Asia.