So far, the company has built a one-eighth-size prototype to test its design, which consists of a carbon-fibre keel, an envelope made from modern composite materials, half-a-dozen engines, a passenger compartment, and a specially lightened crane.

ECONOMIST: Pushing the envelope

The Environment Agency has previously conducted a test measuring the size of wood chip particles in the air, which came back well within the UK limit.

BBC: Wood dust protesters march from Mossley to Plevin plant

North Korea celebrated Memorial Day with an underground test of a nuclear weapon reportedly the size of the bomb that destroyed Hiroshima.

CENTERFORSECURITYPOLICY: Obama��s shrinking deterrent

The Air Force Flight Test Center Museum features a full size replica of Yeager's plane (the real one hangs in the Smithsonian) and actual aircraft that made the region famous.

CNN: Where planes go to die

Lower start-up costs and less strict worker protection make it easier for innovative entrepreneurs in America to experiment on a small scale (hence the smaller size of new firms), to test the markets and to expand.

ECONOMIST: Economics focus

Goldman has gone back to Facebook several times to test the company's interest in expanding the size of the sale, according to a person close to the matter, though the tone of the requests was informal.

WSJ: Goldman Flooded With Facebook Orders