China is unleashing stealth drones and pilotless aircraft fitted with AK-47 rifles onto world markets, racing to catch up to United States (US) technology and adding to a fleet that has already seen combat action in the Middle East.Combat drones were among the jet fighters, missiles and other military hardware shown off this week at Airshow China, the country's biggest aerospace industry exhibition.A delta-winged stealth drone received much attention, highlighting China's growing pr