In a week of thunderstorms it might seem foolhardy flying an airship kept aloft by an envelope containing a bag filled with 63,000 cubic feet of helium.

Historically airships haven't had a good press. The Nazi dirigible Hindenburg crashed in a fireball in New Jersey and the R101, a British government airship, crashed in flames at Beauvais in France after encountering severe weather across the Channel.

They were both filled with explosive hydrogen. Helium is inert. Technology and weather forecasting has progressed.

British pilot Mark Finney has more than 4000 hours in his log book.