For those asking about FS Economy, you can sign up for an account by visiting this page http://www.fseconomy.net/ and reading the “Getting Started” bit down the right side. You have to register for an account on that site and then request a Game World account which you use to connect to the server using your flight sim.
If you want to then join the Air Squirrel group you login to http://server.fseconomy.net/ using your Game World account click on “Groups -> All Groups” and scroll down to Air Squirrel and click Join. It will be submitted for approval.
Note: FS Economy is not a Virtual Airline and you can use it with or without VATSim/IVAO/Pilot Edge.
This is copied from the pinned post in the Flight-Sim-chat in the sub Discord.
Here’s how to get FSE working with the new Microsoft Flight Simulator (you need a FSE Forum account to see the page linked): https://bit.ly/31ktTCb.