I'm not completely up to date with the rules of creators club and I was just wondering, if I created a scenario, and uploaded it, using someone else's livery. Would I need the creators permission to use it in a published scenario (and credit them in the description) or can I just use it without asking them but still crediting them in the description?
No, when a creator uploads a livery to CC, the T&C say that he is granting a license for anyone using TSW/CC to use it.