Survivability over the battlefield was the primary design aim of the A-10, hence the widespread use of armour plating, its duplicated flying control system, twin-engine configuration (suitably spaced such that debris resulting from a hit on one engine would not cause catastrophic damage to the other engine) and high manoeuvrability.
Camouflage is a traditional means of concealing aircraft and its effectiveness may be judged from this photograph of two Harrier GR.5s exercising in northern Norway. For short-term deployments during peacetime, temporary camouflage schemes such as this have been found to appreciably reduce the risk of detection from marauding fighters.
One of the most successful ways of defeating surveillance radars is to fly beneath the radar horizon and hide behind natural 'screens'. Hence the need for low-level training as illustrated by this 13 Squadron Tornado GR.1A skirting a hillside in the Lake District.
With an astonishingly low radar cross-section of only 0.014m2, the Lockheed SR-71 was the first modern aircraft specifically designed with stealth characteristics.
One of the more unusual forms of camouflage was this experimental transparent covering applied to a number of British and German aircraft during World War One. The trials, however, were largely unsuccessful as the cellon was prone to dissolve in strong sunlight and shattered if pierced by a bullet. The aircraft shown here is Fokker E.III 365/16.
Fitted with two Junkers Jumo 004 turbojets, the Horten IX V1 was redesignated the V2. Flight trials began in early 1945, the results of which were put under wraps in a secret US Army operation.
The Go 229 V2 alias Ho IX V2, one of the most radical of WWII's experimental fighters to be flight tested.
The Horten IX V1 was the first aircraft designed from the outset to have a minimum radar cross sectional area. Note the blended wing and body configuration and tail sting. It made its maiden flight in the summer of 1944.
Scale and materials apart, the Horten IX V1 flying wing was not that dissimilar in concept to the A-12 and B-2 which followed almost half a century later.
Although stealth was not a primary requirement of the U-2 programme, Lockheed had amassed a considerable amount of data on stealth technology that was incorporated into the design.