This is how I'm actually taking up people in a 4 seat plane:
Invite someone who wants to fly and tell him it will be FREE (just for him) if he finds two paying passengers.
After you have flown with the 2 pax. you tell them the same story: did you enjoy? It will be free the next time if you find 2 other paying passengers.
In this way you get in touch with more people and the free passenger (call him copilot, works better) will be striving to find people paying to fly.
It works
