So let’s double the speed - 1.2 Ma. You need half the mass now - 25kg/sec. If you want to have 10 seconds worth of hover - that’s 250kg of gas. Plus the weight of the storage tank. Plus - this is the amounts for hover. Not for any extra force on top of that.
It still doesn’t make much sense to me. And that’s before considering what happens when you get rocket stream hitting a tarmac road. Never mind public roads, this sounds like a major hazard anywhere. Plus the quantity of compressed gas son board (if that’s how it works)… not a pretty crash. At these numbers, imagine 10MJ released all of a sudden - apparently that’s about 2.5kg of TNT.
Surely I’m missing something… as I say, I can’t make sense of it.