ZHUHAI (Guangdong) • Two of China's secret J-20 warplanes swept over a gasping crowd at the Zhuhai air show yesterday, potent symbols of Beijing's aspirations to military might.

The fighters were not announced on the schedule and appeared in the sky just after a colourful aerobatics show by the People's Liberation Army Air Force. With no fanfare but an abrupt announcement by the master of ceremonies, the dark, powerful jets rumbled side by side over the sun-baked spectators. Two minutes later, one blasted vertically into the sky and the jets were gone.

Experts say China has been refining designs for the J-20, first glimpsed by plane-spotters in 2010, in the hope of narrowing a military technology gap with the United States.

Beijing is seeking to modernise and upgrade its military both to protect its borders and to project power into regions such as the South China Sea, a resource-rich strategic waterway where it has disputes with several neighbours.

This year's Zhuhai exhibition, the largest ever, features an array of new made-in-China military technology, including assault vehicles and anti-aircraft missile systems.

China is projected to become the world's largest aviation market by 2024, overtaking the US, according to the International Air Transport Association.

President Xi Jinping has declared aerospace one of the target industries for his "Made in China 2025" plan to make the country's companies capable of dethroning foreign competitors in high-value manufacturing and services.

AGENCE FRANCE-PRESSE, REUTERS