This is happening to me as well. Disconnecting internet does not resolve the freeze-up in my case. I’ve tried every other “fix” suggested too but nothing works. One suggestion was removing my custom controller config, but all I have is a game controller. I have this unplugged when the flights are loaded, and it still freezes. I even tried re-installing MSFS itself, but the problem remained.
The only way to get out of the lockup is by entering task manager to kill the MSFS process itself. I’ve tried removing items in the community folder to find which one might be causing this, but I’ve had no luck. It doesn’t seem to be related to any single add-on. Perhaps there is a conflict involving the presence of 3 specific add-on all at once? All I know is, the more add-ons I have in my community folder, the more the likelihood it will lock up when loading a flight. I can remove all or most of my add-ons and it becomes 100% reliable. But the more I add, of any sort, the more the chance of a freeze up. This all started around when I upgraded to SU11. But I can’t be sure that is the cause because that’s around when I started adding a lot of new scenery and aircraft to my community folder. Perhaps there is some performance issue being hit with MSFS SU11 when a certain number of add-ons are loaded at once. If anyone figures, this out, let me know, but in the meantime, the only fix I know of is to load only the add-ons I’ll be needing each time using MSFS.