My two cents. I don't like the part about Weight. Near the surface of the Earth gravity force (weight) is equal to objects mass m multiplied by earth acceleration g.
FG=mg g=9.81 m/s2.
Of course you can set g to one if you wish.
Or, if we want a more realistic model, we can do:

M = (m * G) / h
I think here you meant this equation
FG = GMm/h2
But there is no need for using this formula.
A = U + R + M + F
You have to divide the left hand side by mass of the plane since on the right you have acceleration and on the left forces.

Sorry for not being more constructive, but I am much better at plain physics then aerodynamics.