@TD
I was referring to the duplicated instrument displays on the HUD, not the ordnance aiming capability - which as you correctly state goes all the way back to wartime gunsights and bomb-aiming reticles.
At any rate, the importance of HUD increases significantly in a combat environment where time spent looking down at a console would result in a significant disadvantage - not so for a civil environment (as demonstrated by the piecemeal take-up of the HUD option in the airliners you mention).
Last edited by DozyWannabe; 28th Jun 2012 at 02:50.