The player is in or IS the plane(jet). the problem i have is that i don’t wanna be able to go trough the ground, any help suggestions tips?
Did you put any Colliders on the ground?
If not, then put a Collider on the Ground mesh etc.
And leave it as Static, since the ground will not move.
Here’s a read: Unity - Manual: Introduction to collision
Oh, you should put a Collider and a Rigidbody, on your Space jet plane thingy and on your character too.
Since that moves. 
Check out Rigidbodies too: Unity - Manual: Introduction to rigid body physics
I hope I understood and answered your question well.