The airport is considered to be one of the world’s oldest international airports and Asia’s oldest operating airport. It was officially opened as a Royal Thai Air Force base on 27 March 1914, although it had been in use earlier. Commercial flights began in 1924, making it one of the world’s oldest commercial airports. The first commercial flight was an arrival by KLM Royal Dutch Airlines.
The airport consists of Terminal 1 for international flights and Terminal 2 for domestic flights which are connected by a unique glass exterior elevated walkway. The airport also featured an exterior walkway connected to the Amari hotel.
At its peak in 2004, the airport served almost all air flights for the country, with 80 airlines operating 160,000 flights and handling more than 38 million passengers and 700,000 tons of cargo.
In 2019, the airport reached a maximum capacity of 52 flights/hour or about 700–800 flights/day. Total passenger traffic through Don Mueang in 2019 increased by 1.36%, welcoming 41,313,439 passengers to come here.
According to Wikipedia.