There was a helicopter that used a ram jet IIRC. I guess the only problem there is you need a separate starter motor to get the rotor spinning fast enough for t

There was a helicopter that used a ram jet IIRC. I guess the only problem there is you need a separate starter motor to get the rotor spinning fast enough for the ramjet to take over, but most helicopters have electric starters anyways. Edit: Here's one https://en.wikipedia.org/wiki/NHI_H-3_Kolibrie https://en.wikipedia.org/wiki/NHI_H-3_Kolibrie