Why can't you get it through your head that the plane has to be accelerated to 9.8m/s^{2} to match the earths? Air doesn't have to be solid to accelerate objects. The thread you missed, I bought up indoor skydiving. People are "accelerated" at 9.8m/s^{2} to counter act gravitation.

So Im going to ask again, how can a plane reach terminal velocity if the earth is accelerating towards it?

Dude you are....? By the same way you reach terminal veolocity in a vertical wind tunnel - air is pushed upwards by Earth (like a piston) so at some point the plane will reach 9.81 m/s

^{2} BUT at a latter momment than the Earth (air will take a while to get the plane there), so it will be a difference in their speeds (terminal velocity) that will allow Earth to catch up the plane. I guess you cannot follow simple math equations because you keep asking the same dumb question - that was answered already by those equations.

Go to school, learn about

derivative of a function and come back...

Or special for you: in order to produce the plane accelartion of 9.81, the air MUST push with a certain force on the plane - as in F=m*a. In order to produce that force, the friction of the air on the lane MUST be equal with m*9.81 (m is plane mass). In order to maintan that force, since the air resistance is proportional with the speed, the air MUST flow by the plane with a certain speed. That speed is terminal speed... Doesn't matter if the air is PUSHED past the plane or the plane is ATTRACTED to the Earth, all that maters is that the air has a speed RELATIVE to the plane.