Moving an airplane sized thing that's already in orbit, any push makes it go faster.

Moving it from the ground, you don't just need shielding from the blast, but also shielding from the *air* in front of you.

https://nuclearweaponarchive.org/Usa/Tests/Brownlee.html

This is a manhole cover going 75 kilometers a second; it went too fast to burn. But human beings and most cargo can't possibly survive going from 0 to escape velocity instantly; the speed you'd have to fly would, well, have the time to burn through most things.