[iAidan]

A little bit more 'pro'

pawn Код:

if(strcmp(cmdtext, "/flip", true) == 0)
    {
        if(IsPlayerInAnyVehicle(playerid))
        {
             new currentveh;
            currentveh = GetPlayerVehicleID(playerid);
            if(GetVehicleModel(currentveh) == 519 || GetVehicleModel(currentveh) == 520) // Carry these on with the vehicle id's etc..
            {
                SendClientMessage(playerid, -1, "You cannot do this in an airplane");
            }
                new Float:angle;
                GetVehicleZAngle(currentveh, angle);
                SetVehicleZAngle(currentveh, angle);
                SendClientMessage(playerid, COLOR_GREEN, "Your vehicle has been flipped.");
            }
            return 1;
    }

Untested.