1. How long were you away?
2. How much experience did you have previously?
3. What was your style of gameplay before? Mega-fortress-hub-super-airline? Regional puddle-jumper? Somewhere in between?
Major changes and updates implemented in the past 2.5 years: http://www.airwaysim.com/Information/Whatsnew
UI tweaks and more subtle changes and updates implemented in the past 8 months or so: http://www.airwaysim.com/forum/index.php/topic,58865.0.html
Before you ask:
1. No, there still are no connecting flights. It's on the long-long-long-term wish list.
2. Cargo is in beta testing. It's still very much a work in progress, and this is where the bulk of R&D is focused right now. However, there have been some visible UI tweaks made already to accommodate cargo once it goes live. No obvious references to cargo, just some things moved around.