ZHUHAI, CHINA – China is unleashing stealth drones and pilotless aircraft fitted with AK-47 rifles onto world markets, racing to catch up to U.S. 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 past week at Airshow China, the country's biggest aerospace industry exhibition. A delta-winged stealth drone received much attention, highlighting China's growing production of sophisticated unmanned aerial vehicles seeking to compete with the U.S. military's massive fleet. The CH-7 -- a charcoal-gray UAV unveiled at the air show -- is as long as a tennis court and has a 22-meter (72-feet) wingspan. It can fly at more than 800 kph (500 mph) and at an altitude of 13,000 meters (42,650 feet).