The long-touted idea of using airships to replace cargo aircraft is in the news again, courtesy of former head government boffin Professor Sir David King, who says "this is something I believe is going to happen".

'Fresh fruit, vegetables, flowers and other foreign luxuries' will arrive like this.

King's remarks were reported by the Guardian this week. The former UK chief scientific adviser, nowadays turned big cheese at Oxford uni, was addressing a green biz forum there.

Small blimps used primarily for advertising are still in operation around the world, and a few "Neue Technologie" (NT) zeppelins with semi-rigid structures are used for joyrides. But big heavy-lift airships have not been built since before World War II; the era of the mighty rigids was ended by the disasters which befell the British R101, America's flying aircraft carriers Akron and Macon and then - most famously of all - the fiery demise of the Hindenburg.

According to the Graun, however, Sir David believes that the "US defence department has recently made a large grant to help develop" airship technology.

Presumably Professor King is referring to the recent award of the US Army's $517m Long Endurance Multi-Intelligence Vehicle (LEMV) deal. Much of the LEMV cash will go on developing surveillance systems, but it will also put one or more large "hybrid" airships - based on British technology in this case - into the sky. Sadly the LEMV will be optimised for endurance and height rather than payload, so it won't easily be turned into a cargo hauler.

There is another big-money US military airship project underway, the $400m ISIS strato-spy demonstrator project, but the solar powered radar-envelope ISIS ships will be even less suited to moving freight.

Nonetheless King reportedly considers that air cargo will begin to shift from its present carriers - generally cargo versions of passenger airliners - to airships as soon as ten years from now. This would happen because of the need to reduce carbon emissions, rather than any particular change in the economics of airships versus aeroplanes.