This is my code for free flight movement.
hope it helps.
rem Control player direction
rotate camera camera angle x(0)+(mousemovey()/2.0),camera angle y(0)+(mousemovex()/2.0),0
rem Control player movement
cx#=camera angle x(0) : cy#=camera angle y(0)
if upkey()=1 then xrotate camera 0,0 : move camera 0,0.2 : xrotate camera 0,cx#
if downkey()=1 then xrotate camera 0,0 : move camera 0,-0.2 : xrotate camera 0,cx#
if leftkey()=1 then yrotate camera 0,cy#-90 : move camera 0.2 : yrotate camera 0,cy#
if rightkey()=1 then yrotate camera 0,cy#+90 : move camera 0.2 : yrotate camera 0,cy#
if wrapvalue(camera angle x(0))>40 and wrapvalue(camera angle x(0))<180 then xrotate camera 0,40
if wrapvalue(camera angle x(0))>180 and wrapvalue(camera angle x(0))<335 then xrotate camera 0,335
Not really sure if this is what your asking but this will let you fly around just as the camera in 3D space. But you have to add a loop of course which I didn't do.
Sit in reverie and watch the changing color of the waves that break upon the idle seashore of the mind.
