Windows without a network

On a plane, or without a network, Windows still asks for the second factor: an offline code for that computer. Prepare it beforehand: in the console, under One-time codes, choose Show my offline codes, and scan the computer's QR code with your authenticator app. Without a network, type your Windows password and then the six digits from the app. If you don't have the code, choose Can't use your phone, and support will help you, even offline.