Yes you are able to start a project if you are working offline.
one thing to consider is that you will not have access to any of the online assets.
if you have Unreal engine launcher you can start a new project and place it were you want it.
one tipp from me is download assets you want to use and especially the things from quixal bridge and save that folder on the offline laptop too.
that way you are able to use some of the assets in your project.
you will allways be able to open a project from a usb or a external harddrive, but depending on usb type and how fast is can read and write it can slow down your process when working.