I'm still flying my P1s. As I understand that at power up the quad should be level and not moved so the gyro stabilization takes place. After that I don't see hand launching being a problem although I have never done it. I have caught them and powered up again to fly. It's about the same thing. I don't know if the P2, P3, and P4 needs to be level at power up. I would think so. If they do need to be level at start up, I think that would be difficult on a boat or on the side of a hill etc.