We have no consensus on what "most people fly by", If we are honest.
Being that flightgear is a free simulator, that fact alone might go far to weighing towards the usage of the simulator by people that might not afford additional hardware. If this weighing is taken in consideration, then one could make the argument that "most people fly by keyboard and mouse" because they are not willing to pay for 'pay-for' simulators or additional hardware.
People often have a misconception of who uses flightgear. "Most people" using flightgear never speak in the forum, never run on multiplayer, don't post to the wiki or the mailinglists... on and on.
We should differentiate from "most people" and "most people I am aware of".
100's of thousands of individuals have downloaded, installed, and used flightgear at one time or another.
Yet, only 5791 have ever joined this Forum. Maybe less than 1000 installers ever use multiplayer networks, certainly less than 80 people are logged into multiplayer at any given time, and often as low as 10.
We should be careful when we assume we know the Flightgear audience. Personally, I believe we've never been properly introduced.
Making these fixes to the way flightgear is advertised goes a very long way to building it's credibility with an audience we shall never truly know.
-- Ray