...Western defense officials and experts were surprised to see more than 25 different Chinese models of the unmanned aircraft, known as UAVs, on display at this week's Zhuhai air show in this southern Chinese city. It was a record number for a country that unveiled its first concept UAVs at the same air show only four years ago, and put a handful on display at the last one in 2008.

The apparent progress in UAVs is a stark sign of China's ambition to upgrade its massive military as its global political and economic clout grows.

The U.S. and Israel are currently the world leaders in developing such pilotless drones, which have played a major role in the wars in Iraq and Afghanistan, and which analysts say could one day replace the fighter jet.

This year's models in Zhuhai included several designed to fire missiles, and one powered by a jet engine, meaning it could