FlyX, actually, if you drop a penny and a quarter from a high enough tower, they won't hit the ground at the same time at all.

They WOULD if you did the experiment in a vacume. whats-his-name with the spheres way back when got kinda lucky in that he picked objects and an envrioment where the air resistance was not a measureable factor using his available tech. Because we aren't flying our models in a vacume. In fact, entirely the opposite, we are interacting with the air in all kinds of ways.

So, take a glider, trim for best glide, and throw it from a tower. If you measure the distance flown vs. the height dropped, you get a ratio that just so happens to match the Lift/Drag ratio of the glider. Now, add weight, and repeat the experiment. You get the same glide path, the same L/D ratio. (as long as you don't over-do it with the weight). So the glider will wind up at the same spot, however, it will do it faster, spending less time in the air.

The reason is that the airfoil is most efficient at a particular AOA. That's your best glide and best L/D ratio. That AOA is half of creating lift. The other half is airspeed. So, if you keep the AOA constant (most efficient spot), then you have to increase airspeed to increase lift to match the increase in weight. A glider will do this for you if you have it all trimmed out right.

In powered flight, if you add weight, you have the same thing going on. Either you increase airspeed to increase lift, or you increase AOA to increase lift. If you increase airspeed, then you fly faster, and come down faster. If you increase AOA, then you fly at the same airspeed, but you're closer to stall, and since you're at a higher AOA, you have more drag being created and the airfoil isn't as efficient.

Now, that doesn't mean that a higher wingloading makes you go faster. It means you are forced to fly faster (if you can) to produce enough lift to stay in the air. If you want to go fast, you want the lightest thing you can shove the biggest engine into. And you want the wing to be as efficient as possible, which means you want the AOA in level flight to be at the airfoil's most efficient point. That means that the wing has to be big enough but not too big.

Too small a wing, and the wingloading is too high, your AOA is high, and the drag is high, and you go slow at full power.
Too large a wing, and while the wingloading and AOA are low, you're moving more airplane through the air than you have to, and creating more drag than you need to.