The 80's AirForcesupercockpitprogrambuiltfighterpilotheads-updisplaysintosomereallybulkyhelmets.
In 2018 Microsoftgotthat 480 milliondollarcontractwiththeUSArmywhichcouldgetupto a hundredthousandHoloLensheadsets, bothfortrainingandforgivingsoldiers a heads-updisplayinlivecombat.