The canon ball and the feather fall at the same rate in a perfect vacuum.

You can't jump out of a flying airplane in a perfect vacuum, because an airplane can't fly in a perfect vacuum.

A falling object, in the atmosphere, reaches a terminal velocity when the aerodynamic drag due to moving through the air is equal to the weight of the body. The aerodynamic drag is proportional to the frontal cross-sectional area presented in the forward direction of falling, for bodies of fairly similar shape.

When you change the size of a body by direct scaling, the weight/mass varies as the cube of the dimensions, but the areas (frontal, surface, cross-sectional etc.) vary only as the square of the dimensions.

If an otherwise identical body is scaled to be twice as large in all linear dimensions, the areas will be four times as large but the mass/weight will be eight times as large. Since there will be eight times as much "pulling down" force (the weight), and at the same speed there will be only four times as much "holding back" force (the air resistance) the "larger" object will continue to speed up after the original object reaches its terminal speed, if the two are released together.

Since the aerodynamic drag varies with the square of the speed through the air, the terminal velocity of the "two times as big" object will be approximately 1.4 (the square root of 2) times the terminal velocity for the "original" object.

To the extent that males and females are "similarly constructed," the observed tendency that males are usually larger than females is adequate to explain the generalization that the male will hit the ground first if a "typical male" and a "typical female" both exit an airplane that is in flight, and both fall freely to the ground.

Again referring only to "averages," there are slight general trends that give "typical females" a slightly higher fraction of "adipose tissue" which tends to additionally cause them to have very slightly more "cross section" for a given weight than for a "typical male" of the same weight (Adipose, or "fatty" tissue is less dense than muscle tissue.) This also would tend to give the female a slightly slower terminal free-fall velocity in air than a male of the same weight, although the difference would be quite small.

This difference appears, from personal observation, to be rapidly disappearing, as the kids - of both sexes - that I see around the schoolyards seem to be mostly blubber. (That may be a local phenomenon, but reports are it's fairly general.)

The observation immediately preceding may render this entire thread completely academic at some future time. Since adipose tissue produces and secretes "female" hormones, including estrogen, children of either sex who are obese before or at the time of puberty tend to be "feminized" in their development. The development of "male" secondary sexual characteristics is inhibited, so in a few years at present rate all our little boys and little girls may be "little girlies" (in outward appearance, at least).

John