How to start with camera and Airplane for the game ?

I am new to the unity and I am trying to make game like Air Strike 3D .I am facing few difficulties at the initial stage. I am not able to recognize how is the AirStrike3D camera working and Airplane working.

is Camera constantly moving in Z direction and Airplane is following camera ?
or is Airplane constantly moving in Z direction and Airplane following it ?

How to go about it ?

you could possibly think of it in a different manner.

the camera doesn’t move and the plane is confined to the space on screen, then just move the terrain with the stuff on the terrain parented

this is the method i use for my top down shooter, now granted this one adds perspective and a complex 3d terrain, but really all you have to do is create your terrain in an app like 3ds max and animate the terrain on the path you want, link a finish collider to the end and walla! theoretically it should work, even with ground enemy’s or turrets.