The point I was trying to make was that Gravity causes an equal rate of arceleration for all things. There are forces that change this rate of arceleration, including friction and momentum.
For a more accurate version of that experiment, get a wooden and an iron ball of equal size, and drop them from the tower of Pizza. They will land at the exact same moment. (Then get arrested by the Spanish inquisition for telling the world goes around the sun)
An airoplane would continue going forward, while the person stepping outside would fall down.
Both would enter a parabolic trajectory, but the planes descent is slowed by the lift of it's wings. The person, being quite a bit less
aerodynamic, and also much lighter would be slowed down by friction, and will, depending on the hight of the fall, land first.
The actual density of the plane doesn't impact it's flight trajectory much. It just means the thing has more momentum and is thus less impacted by other forces, for example friction and it's engines power. It doesn't have any effect on gravity, because while the energy required to move it does increase with mass, so does the gravitationall pull.As far as I can remember the calculation goes a bit like this. (Note, friction is ignored).
(m*vē/2)=m*g*h (m=mass, v=speed, g=gravitational force, h=height)
As you can see the mass cancels itself out, and therefore doesn't influence arceleration.
So far for physics 101;