A British-designed, solar-powered aircraft has broken the endurance record for an unmanned air system.

The Zephyr, currently flying over Arizona in the US, has passed the seven-day mark and is expected to fly for another week. UK defense technology company QinetiQ, has developed the plane.

The aircraft has already doubled its own unofficial record of over 82 hours and smashed the previous world record for unmanned flight of 30 hours and 24 minutes, set in 2001 by U.S. aerospace company, Northrop Grumman`s RQ-4A Global I.

Zephyr program director Jon Saltmarsh said: "The team has worked tirelessly over the past few years, making truly significant leaps forward in overall design and construction - and to see it successfully soar into the sky was fantastic.

The aircraft flies by day on solar power delivered by amorphous silicon solar arrays no thicker than sheets of paper that cover the aircraft`s wings.These are also used to recharge the lithium-sulphur batteries, which are used to power the aircraft by night.

QinetiQ says it will save the military money, performing many of the tasks currently carried out by manned aircraft. It will also find a civilian use helping communications in disaster relief situations, as well as forest fire monitoring.

The aircraft flies by day on solar power delivered by amorphous silicon solar arrays no thicker than sheets of paper that cover the aircraft`s wings. These are also used to recharge the lithium-sulphur batteries, which are used to power the aircraft by night.

BDST: 1655 HRS, 18 July 2010