I picked up this Logitech Wingman joystick at my local used computer store. It works pretty well with the Google Earth Flight Simulator to control aileron and elevator movements. The small silver handle at the lower left is the throttle control. For flaps and rudder, I still have to resort to the keyboard. The simulator actually works fine with a mouse, but the joystick is more intuitive and more fun.
Serious sim players are more likely to use a box with a couple of thumb sticks like the fellow in the picture below made at Albuquerque's Balloon Museum. He is operating a sophisticated radio control model simulator with the same kind of controller that would be used to directly operate an rc model. While it may be a bit ironic to be simulating a simulation, the strategy does have the practical benefit of getting practice on the same equipment that will be put to use when an actual flying model is at risk.
The Google Earth Flight Simulator has built-in support for a number of joysticks. The path to the initialization files is C:\Program Files\Google\Google Earth\client\res\flightsim\controller. An explanation of the button assignments will be found in the generic.ini file.
The guide to the flight simulator keyboard controls is at the Google Earth site.
An aspect of all this that appeals to me is the opportunity to move easily back and forth between the real and the imagined. Someone who considered that idea a good while ago was the author who coined the term, "cyberspace", William Gibson. In 1985, together with Michael Swanwick, he produced the short story, Dogfight in which the main character becomes obsessed with a game of combat by tiny holographic WWI fighter planes which are controlled directly by the mind. That is probably my favorite of Gibson's work. I think I lost the anthology in which it appeared, Burning Chrome, during our last move. There is a pirated copy of Dogfight parked on a Russian server, but the other stories in the collection are worth reading as well.