A gun-fired projectile or ballistic missile (1) is equipped with a pair of canards (3) and an array of tail fins (2). Selected tail fins can be retracted or jettisoned following the ballistic phase to vary the geometry of the array from a rotationally symmetrical configuration to an asymmetric configuration for the glide phase, which together with the canards tends to stabilize the projectile in roll. The canards (3) can be independently extended and retracted with respect to the body of the projectile to generate differential lift for banking the projectile to turn. The canards (3) also preferably have a positive dihedral angle with respect to the intended gliding attitude. In an alternative embodiment the canards are replaced by functionally equivalent thrusters.