Over on their forum page, Orbx have provided a roadmap for their numerous upcoming products. It includes city packs, regions, airports and also aircraft:
We realise we have not announced any product roadmap for a while, mostly due to putting efforts on planning around the release of microsoft flight simulator and understanding what was possible. After a few months, and a few more products, we feel now it's a good time to draw up a list of products which we are planning to release in the next little while.
Now - we know in flight sim (and in life!) things can change fast, so we reserve the right to modify the list and the sequence, so best to keep checking our "coming soon" page to be up to date with what is coming next.