Head mounted displays (HMD) and corresponding display methods are provided, which obtain, repeatedly, from a monitoring system of a vehicle and, a reference vector relating to the vehicle; display on the HMD a reference symbol that indicates the reference vector; and determine movements of a HMD symbology according to a spatial relation between a received user's line of sight (LOS) and the reference vector. For example, the vehicle may be an aircraft and the reference vector a flight path vector (FPV) received from the aircraft's avionics. The proposed HMD enhances the displayed information content while avoiding excessive movements of the symbology. The HMD's functional parameters may be pre-set or adapted according to user preference and flight stage characteristics. The reference symbol anchors most of the symbology, while minimal critical information may be moved along with the user's LOS, providing a clearer and more stable view through the HMD.