Hydrogen engines: is there nowhere they haven’t appeared? Cars, buses, vans – all have succumbed to the charms of hydrogen. At this rate, if you look down the back of the sofa, there will probably be one there too.

And now, The Telegraph reveals, you can find one on a Boeing plane:

Last month Boeing successfully tested the unit with a multi-stage turbocharger running continuously over four days, including simulated conditions at 65,000 feet. The HALE aircraft are designed to stay in the air for seven days, carrying up to 2,000lb and maintaining communications links or surveillance over specific areas.

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