They can probably easily shoot most of the cockpit scenes. Heck, they could even ship the cockpit set over to the states if they needed to.

Body doubles are used more than people realize, (eons before CGI existed) even when an actor hasn't been injured. Long shots, inserts, etc. They don't pay an actor to stand around for shots where their face isn't visible.

I'd be willing to bet a rig could be built to shoot Harrison from the waist up which could give the illusion he's walking. Necessity is the mother of invention. ;)