WHILE CHINA’S NEW SPACE-AGED J-31 stealth fighter is designed to be virtually invisible, Beijing’s trumpeting of the new aircraft has been anything but inconspicuous.

After unveiling the low-observable supersonic jet at the country’s national airshow earlier this month, the international media is reporting that the People’s Republic hopes to make billions selling the revolutionary warplane to foreign powers – namely Pakistan.

And it’s shaping up to be a crowded market for stealth technology. Currently, more than eight nations are developing low-observable aircraft, including India, Iran, Russia, Sweden and even Turkey. But while stealth is still considered at the bleeding edge of aviation technology, from the very dawn of aerial warfare, aircraft designers have sought to make fighters and bombers invisible to the enemy. Here are some examples of stealth warplanes from early to modern.

While ordinary aircraft camouflage made its appearance during the First World War, it was German engineers that set out to build the world’s first invisible warplane. Researchers behind the ambitious plan discarded the canvas skin on experimental Fokker monoplanes, as well as bombers and even Albatross scout planes and replaced the drab painted fabric with a translucent cellon acetate – the same material used in the manufacture of early film. While the wooden airframe would still be visible underneath the coating, it was hoped that light passing though the clear exterior skin would make German aircraft virtually imperceptible from long ranges. Unfortunately for the designers, early tests revealed that the revolutionary see-through material actually made the aircraft more visible – the glossy nature of the sheath reflected sunlight. The project was shelved indefinitely.Interestingly, Russian designers with the Nikolai Zhukovsky Air Force Engineering Academy engineered an ‘invisible’ Yakovlev AIR-3 monoplane with a cellon skin too.While the material offered the pilot a much wider field of vision, engineers found the glare from the shiny coating made the aircraft highly visible in bright daylight conditions.

With the advent of radar at the outset of World War Two, the race was on to design a warplane that was undetectable by the revolutionary new range-finding technology. British aircraft designers got out to an early lead with the De Havilland DH. 98 Mosquito. Introduced in 1941, the twin-engine, fighter/bomber’s airframe was constructed of radar absorbing plywood. While not specifically designed to be stealthy from the outset, the plane’s low signature as well as its top speed of nearly 600 km/h (375 mph) made it a tough target to track for Axis radar operators.

It’s often been claimed that Germany’s Horten Ho-229 was designed from the start to evade radar. Everything from the experimental jet bomber’s revolutionary flat flying wing design and its lack of vertical tail fins to its wooden frame paneling and charcoal glue coating was supposedly engineered to render the aircraft undetectable to Allied sensors. Not everyone is convinced however that the Nazis were even thinking of stealth when developing the envelope-pushing warbird. According to some sources, the unconventional design was chosen largely for aerodynamics. Nevertheless, the Ho-229 (which was also known as the Gotha Go-229) first took to the skies in March of 1944. The Luftwaffe was immediately impressed and ordered 40 of the jets; only three were produced before the Third Reich collapsed. Aware of the existence of the radical new aircraft at the war’s end, American agents raced into the heart of Germany to smuggle out the prototypes before they could be captured by the Soviets. One airframe was recovered. It was eventually added to the Smithsonian Air and Space Museum’s collection. Decades after the war, engineers from Northrop supposedly studied the surviving Ho-229. Its design helped inform the development of the B-2 stealth bomber.

When the U.S. military launched its controversial invasion of Panama on Dec. 20, 1989, it marked the official combat debut of one of America’s most secret weapons, the F-117A Nighthawk stealth “fighter”. The dart-shaped, single-seat, sub-sonic attack aircraft featured angled surfaces that were engineered to deflect radar energy away from the signal source. The wings and fuselage were also coated with special radar absorbent materials. While roughly the size of a F-15 fighter jet, the 25-ton aircraft generated a radar signature roughly equal to that of a baseball. [1] The stealth also featured cowls fitted overt the exhaust vents to diffuse heat thereby reducing the aircraft’s infrared signature. Developed under a cloak of secrecy between 1978 and 1981, the $111-million apiece warplane first went operational with the U.S. Air Force in late 1983. Details of the plane’s existence weren’t announced however for another five years. The Pentagon eventually ordered 64 stealth fighters, the last of which was retired in 2008. Despite a lengthy combat service history that included missions over Iraq, the former Yugoslavia and Afghanistan, only one F-117A was ever brought down by ground fire. That was during the Kosovo War. Wreckage of the lost Nighthawk is on exhibit in the Belgrade aviation museum.

America’s second stealth warplane, the Northrop B-2 Spirit, first entered service in 1989. The strategic bomber was designed to haul a 50,000-pound payload more than 6,000 miles at speeds approaching Mach 1. Inspired by earlier ‘flying wing’ designs like the Nazi Ho-229, the rudderless, $2-billion aircraft was designed to be virtually invisible to enemy air defences. In fact, to enemy radar the massive aircraft appears no larger than a volleyball. [2] The B-2 first saw combat over Kosovo in 1999. It later went onto serve in the air campaigns against Iraq, Afghanistan, Libya, and most recently Syria, often striking its distant targets from bases inside the United States. The USAF currently maintains a fleet of 21 stealth bombers and expects to retain the aircraft well beyond 2050.

America’s current frontline air superiority fighter, the F-22A Raptor was also designed for stealth. Nearly 200 of the $150-million dollar supersonic warplanes are already in service with the U.S. Air Force. In fact, a formation involved in the raids on ISIS in September undertook the class’ first ever combat mission. The F-22 will soon be joined by an even newer American stealth aircraft: the multirole F-35 Lighting II. The Lockheed Martin fighter/attack platform is expected to enter service with the air force, navy and marines over the next two years. It’s also slated for export to a number of allied nations, including Canada, the United Kingdom, Japan, South Korea and Israel. The program has been famously fraught with problems however, and recently some foreign buyers have balked at the mounting costs and perceived shortcomings of the design. Meanwhile, other competing powers are already fielding stealthy fighters that are expected to match the F-35 in capability. These include Russia’s Sukhoi T-50 and (yup, you guessed it) China’s J-31.