Where can I go to get any airplane skins/liveries, or new aircraft.
Look in the upper right corner of this page.
You'll see a object that looks like a magnifying glass.
Press that and the search box will open.
You'll have many hundreds of download choices that fit your request.
Load one at a time so that if something is wrong with the Sim when you try to fly it you'll know which add-on caused it.
We have free scenery too.