China is catching up to the US in developing unmanned drones and plans to sell computerised warplane machines to customers in Pakistan, the Middle East, Africa and throughout the world, according to a report in The Washington Post . Chinese aerospace companies unveiled 25 unmanned aerial vehicles (UAVs) during the Zhuhai air show in southern China last November, five years after the first Chinese drone flew at a demonstration. The US stands like a giant above the rest of the world in military supremacy and is far ahead in drone technology and associated satellite and sensor technology. But more than 50 countries had either bought or begun researching surveillance drones from 2007 onwards, according to US Air Force drone expert Lt. Kendra L.B. Cook. Richard Fisher is a senior fellow at the Washington-based International Assessment and Strategy Center and predicts that the rest of the world could start catching the US. The Chinese are catching up quickly. This is something we know for sure, Fisher told The Washington Post. We should not take comfort in some perceived lags in sensors or satellites capabilities. Those are just a matter of time. Every major manufacturer for the Chinese military has a research center devoted to drones, Chinese analysts told the Washington Post. In 2011, the market for drones has increased, and Chinese companies are expected to fill the demand. Global spending on drones will double to $94 billion by 2021 with the US accounting for nearly 70% of purchases, according to a 2011 market study by Virginia-based Teal Group. Many nations have access to some surveillance UAVs, but few have drones with weapons. Nations covet US drones because they are relatively cheap and undetectable scouting weapons that could put soldiers further away from battlefield harm. According to The Washington Post, drones can save hundreds of millions of dollars. A single F-22 fighter jet costs $150 million, while General Atomics Aeronautical Systems manufactures the high-end Predator B drone - or MQ9-Reaper - for $10.5 million. Ground troops can even hand-launch drones costing tens of thousands of dollars. The Chinese Peoples Liberation Army (PLA) gets many of its high-tech aircraft from the Chengdu Aircraft Design and Research Institute, a company looking to profit from global drone demand.