You can also use a joystick.
If you joystick is an old but trusty sidewinder btw.
And if you find out that your throttle lever and rudder axis have each other functions, the fix is:
You go to C\Program File\Google\Google Earth\res\flightsim\controller
You open the "generic.ini" with notepad
And where it says:
A1 set(DE, 1.0, 0.0)
A0 set(DA, 1.0, 0.0)
A2 set(DP_0, -0.5, 0.5)
A3 set(DR, 1.0, 0.0)
You replace it with:
A1 set(DE, 1.0, 0.0)
A0 set(DA, 1.0, 0.0)
A3 set(DP_0, -0.5, 0.5)
A2 set(DR, 1.0, 0.0)
(save)