How to stop character pushing vehicles

Hi, I’m relatively new to blender and I’m currently working on a game in which a character can get into vehicles however i’m having several issues with logic bricks:
A) The character can only jump once using the ‘character motion’ ‘jump’ feature in logic bricks and once the character has jumped once, it doesnt jump again even if I press the space button (not double jump, but jumping later from the floor)

B) The character can easily push vehicles that the character isn’t supposed to e.g. the character can walk into and push a chinooke helicopter.

Please tell me how I can fix either one of these, thank you.

A) What makes your character jump?

B) I guess your Helicopter has a mess of 1.0, isn’t it? What is the mass of your character? What makes your character move?