My thirty year old hangar is now finally insulated! I hired a company to put in blown foam insulation. This foam conforms to the shape of the hangar interior walls as it dries, and almost looks like regular texture you would see in a home with sheetrock walls. It dries within minutes and is paintable in the same day. It also seals the entire hangar, preventing bugs from getting in. My wife loves it!

Check it out!
https://www.youtube.com/watch?v=pQ0QSBmyaQ4