A vehicular head-up display (HUD) for displaying an image to a user of a vehicle having a windshield (15) includes an image projector (14) outputting a collimated image and an optical aperture expander. The optical aperture expander includes a light-guide optical element (LOE) (10) having two major external surfaces (30a, 30b). The image projector (14) injects the collimated image so as to propagate within the LOE by internal reflection at the major external surfaces. The LOE also has a set of parallel partially-reflecting internal surfaces (12) which progressively couple out the image illumination from the LOE. The optical aperture expander is deployed such that the image illumination coupled-out of the LOE (12) follows a light path including a reflection from a surface associated with the windshield (15) of the vehicle so as to be visible to the user while the user looks at a scene beyond the windshield.