The first regular flights from/to Singapore to/from Europe operated out of RAF Seletar. The RAF air station, which was completed in 1930, played host to the first regular air services connecting Singapore with the Dutch East Indies (now Indonesia) from 1930. Connections with Europe would take a few more years and in May 1933, the Royal Dutch airlines, KLM – the world’s oldest airline in May 1933 introduced regular services from Singapore to Europe. Using a Fokker F.XVIII, the outbound journey took seven days and inbound eight days – with multiple stops.
Flying then was not for everyone of course. It would have cost an arm and a leg and maybe a little more with a single ticket from Singapore to London priced in excess of £164. That would be the equivalent of £11,815 or more than SGD 21,000 in 2020!

Air Travel between Southeast Asia and Europe in the 1930s.