From Wikipedia:
In 2010, based on the notion that Coandă invented the first jet, the centennial of the jet aircraft was celebrated in Romania.
This aircraft was built by Henri Coandă, he of the effect that the NOTAR helicopter is based on. It was part of an aviation exposition in Paris, in 1910. Claims that it has actually flown are disputed, but not everywhere in the world apparently. The engine was a 50 hp piston engine driving a cowled fan.