Installation on an offline computer?

Another help Q&A said that it can be done, but I thought that I should ask to make sure before I shell out the 1500$ for pro.

The computer I’m using for my game development hobby(possibly business later) doesn’t have any internet or network access (done on purpose for various reasons) and I use flash drives to transfer data back and forth to this computer.

Also if I can install and use Unity on an offline computer do I have to keep validating the license at regular intervals like Game Maker?

Thanks in advance

Yes you can install on an offline computer - the relevant page of the documentation for Unity 4 is here: Manage your license | Unity Hub | 3.0