lots of threads with good advice on this very topic on Reddit. I found these just by putting "site:reddit.com shipping desktop" into Google: https://lmgtfy.com/?q=site%3Areddit.com+shipping+desktop

good luck with the move [+]

Yes.my advice to use airplane for shiping becos it will go on the sky and boat will go on water and perhaps cause damage to pc component due to moisture. Thx

Don't. Let go of it and let your new life begin.

dont be a neet in scotland

Remove CPU cooler + GPU (and any other PCIE devices), probably also hard disks/disk drives/anything else shock sensitive

Pack all of that into your carryon along with peripherals. Computer case (with motherboard and other remaining 'secure' hardware) goes into a large suitcase packed with clothing.

Can also ship the case in its original box/padding ahead of time, but that's more expensive than checking it in my experience.

Source: I've done this >15 times in the last 4 years.

If it wasn't Scotland I'd probably agree.

recently brought my desktop from Bulgaria to Germany. Basically what I did was pack it in a shit ton of plastic and bubble wrap in it's original cardboard box. that shit didn't move an inch on the flight I'll tell you what.