I use the typical WASD for ground vehicle movement, QWEASD for planes and helicopters.
I have Radar/IRST cue control bound to Alt + WASD and tilt control to Alt + QE.
On a plane I can hold down Alt and adjust the radar cue control and tilt using QWEASD without any effect on pitch, roll or rudder and when I let go of Alt I can control the plane with QWEASD.
However if I try this exact same set-up with either a ground vehicle or helicopter holding Alt + QWEASD it both effects radar cue/tilt and provides control inputs to the vehicle, driving my SPAA or pitching my helicopter about!
Is there a reason for this discrepancy? I have made sure to investigate any conflicting keybinds, Alt is neither my free look key nor show mouse cursor.