I might have found a bug. I installed your mod yesterday, and I was developing a plane in sandbox game.
Yesterday everything was fine, but today (after the update) when I returned to the very same vessel a strange bug started occuring. Whenever I revert the flight to the hangar, I can't do anything. Neither of "launch", "load vessel" "exit hangar" buttons work. Clicking them does nothing. The only thing I could do was ALT + F4.
I do use a dozen or two of mods, but after some troubleshooting I deleted CNC, and the bug stopped occurring.
Now, I initially installed 1.5.3 version of your mod yesterday, but yesterday everything was fine. I don't know if it automatically updated itself to 1.5.4 (I installed from spacedock) but I assume it did, as the problem started today, which is after the update.
The bug wasn't caused by the vessel itself, as the same thing happened with stock vessels.
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Edit.
Okay, I did some more testing. I deleted whole CNC mod folder, redownloaded clear isntall of 1.5.4. and started a new (3rd already) sandbox game. The bug is not happening. Then I loaded 2nd sandbox again, the one I started today in the morning, and reverting the flight yet again causes the bug. That is very strage. In both games I use exactly the same vessel, copied from one save to another.
It may be some incompability with old 1.5.3 modules loaded into the vessel. That is very frightening, as in my main career save I have already used the 1.5.3 mod.