Size doesn't really make that much difference to making an aircraft fly. Large or small the same principle applies. So long as you have enough thrust to pull air over an aerodynamic surface large or efficient enough you can make pretty much any size of aircraft fly. Which is why you generally see more engines on a larger aircraft and a larger wing/tail area.
To be honest this aircraft is small compared with some aircraft that have flown. The B-36 peacemake for example.