I respectively disagree
a hard vacumn is not required.
just a lower pressure in front than behind.
pneumatic tubes have been used for small parcel (money, letters sales receipts)
for a hundred years.
just scale it up.
if 750mph isn't dooable?
so what.
75 mph would work.
"just scale it up"
I think this oversimplifies things a little. :)
mouse- elephant
guppy- whale
chihuahua- great dane.
I don't see the problem