i have a kind of greatsword made by a local smith. is not keen but is made with the blade in stainless steel, iron hilt, iron grip covered by several layers of synthetic leather. weights about 1.7 kilograms and is 118 centimeters long. sometimes i go in the garden random swinging around. today i tried to jump forward and side slash. is possible BUT you can't stop the swing mid air (i think it's because you need waist force together with firm legs on the ground). doing a overhead jumping is easy. swinging sides is a bit weird but doable... without stopping it (like unbalanced weapons) and the thrust is comfortable BUT in the landing part. thrusting in the first part of the jump feel a bit stupid.
i don't have a cam so don't troll me about "no proof".
I believe you have tried all that, but now think how it would be with an enemy who blocks your hit or you really aiming for someone and the guy dodging so you just miss. Hitting through the air is one thing. But aiming for something and then not hitting cause of a dodging target is something completely different. I know what I'm talking about as I'm doing martial arts for more than 12 years now.
Hard to explain everything on my mind in English, can't we just speak German?^^
If you jump and a person blocks your hit, all your energy is stopped or redirected to another direction. As you are midair, you have no ground to get a stable position, means you are like a ball getting a hit midair. You change your direction and the chance you land on your feet without stumbling or falling is very small in that case. ---> makes it more or less impossible to use that in a fight ;)
What happens when you jump and hit with all your power and your target is just ducking under your swing so it continues, you can figure our yourself^^
Fact is, jumphitting might be possible, but it is useless and not doable while fighting