Walk animation when on ground

hey guys, need help making my guy preform the walk animation when he is on the ground, my guy has a jetpack and has a idle in air animation and on click animation that both work fine, but i dont know how to go about making him play his walk animation only when he is touching the ground, thanks.

Check this question, it is the same:

http://answers.unity3d.com/questions/196381/how-do-i-check-if-my-rigidbody-player-is-grounded.html

Use a character controller and check if he is grounded.
The other way is by checking its transform.position.y.