The two-seater motor-glider, built by an Austrian firm, was modified by Boeing engineers based in Madrid, Spain, to include a fuel cell and lithium-ion battery hybrid system.

During a series of test flights in February and March the pilot climbed to 1,000 metres (3,300 feet), and flew at a cruising speed of 100km an hour (62mph) for approximately 20 minutes.

Boeing researchers said the technology could potentially power small air vehicles and be used for back-up or auxiliary units on large aircraft, but it is unlikely it will ever provide primary power for large passenger aeroplanes.

However, bosses said the company will continue to investigate the potential of hydrogen fuel cells and other alternative fuel and energy sources.

“Boeing is actively working to develop new technologies,” said Francisco Escarti, managing director of Boeing Research & Technology Europe (BR&TE).

“We are proud of our pioneering work during the past five years on the Fuel Cell Demonstrator Airplane project.

“It is a tangible example of how we are exploring future leaps in environmental performance.”

The engineers linked the fuel cell and battery system to an electric motor, which was then coupled to a conventional propeller.

The pilot used the fuel cells and battery to reach high altitudes before disconnecting the battery and cruising on power solely from the fuel cells.

BR&TE has worked with Boeing Commercial Airplanes and a network of international partners since 2003 to design, assemble and fly the experimental aeroplane.

The partners include UK-based hydrogen fuel cell manufacturer Intelligent Energy, which recently announced a deal with Suzuki to develop hydrogen fuel cell-powered motorbikes for the mass market.

Aeroplanes powered by liquid hydrogen and hydrogen fuel cells have previously taken to the skies but did not have anyone on board.

Last month, Virgin Atlantic conducted the first test flight of a Boeing 747 fuelled solely by biofuel.

Kate Martin

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