Zephyr is a series of lightweight solar-powered UAV originally designed and built by the United Kingdom company, QinetiQ.  and is now part of the Airbus High Altitude Pseudo-Satellite (HAPS) programme. 
The Zephyr 7 holds the official endurance record for an unmanned aerial vehicle for its flight from 9 July to 23 July 2010, lasting 336 hours and 22 minutes (2 weeks / 14 days). Record claims have been verified by the Fédération Aéronautique Internationale (FAI) for both duration and altitude, at 21,562 meters. It more than doubled the previous endurance record for unmanned flight.
In a 2008 demonstration for the US military, a smaller-scale version of the Zephyr (Zephyr 6) performed beyond the official world record for the longest-duration unmanned flight, however its 82-hour flight at an altitude of 61,000 feet did not set an official record because FAI officials were not involved in the flight.
It is of carbon-fibre construction, and uses sunlight to charge a lithium-sulphur battery during the day, which powers the aircraft at night. The aircraft has been designed for use in observation and communications relay.
The vehicle can circle over a particular area for extended periods. The military uses the vehicle for reconnaissance and communications platforms. Civilian and scientific programmes use it for Earth observation. During the day, Zephyr uses its state-of-the-art solar cells spread across its wings to recharge high-power lithium-sulphur batteries and drive two propellers. At night, the energy stored in the batteries is sufficient to maintain Zephyr in the sky. The lithium sulphur batteries are supplied by Sion, and the first version had a battery capacity of 3kWh.
Zephyr 7 is bigger and takes five individuals to launch, as opposed to the three previously. The team runs gently into the wind until it lifts out of their hands. Zephyr 8 is now under development and will be bigger still, with a 28 metre wingspan.
The Zephyr system was sold to EADS Astrium (now named Airbus Defence and Space) in March 2013 where it has successfully re-flown as part of the High Altitude Pseudo-Satellite (HAPS) programme  In 2014 it flew for 11 days in winter.
Data from -->
- Crew: none
- Payload: 2.5 kg (5 lb)
- Length: ()
- Wingspan: 22.5 m (73 ft 10 in)
- Height: ()
- Loaded weight: 53 kg (116.8 lb)
- Powerplant: 2 × 450W Newcastle University custom permanent-magnet synchronous motor, () each
- Amos, Jonathan (2003-06-24). "Strato-plane looks forward". BBC News. Retrieved 2014-03-31. "British engineers are preparing to push the limits of aeroplane technology"
- "First flight of Astrium's Zephyr solar HAPS". Airbus Group. Retrieved 31 March 2014.
- Amos, Jonathan (2010-07-23). "'Eternal plane' returns to Earth". BBC News. Retrieved 2010-07-23. "touched down at 1504 BST ... on Friday ... took off ... at 1440 BST (0640 local time) on Friday, 9 July"
- "FAI Record ID No. 16052". Fédération Aéronautique Internationale. Retrieved 4 December 2012.
- Hanlon, Mike (23 July 2010). "QinetiQ Zephyr solar powered unmanned aircraft to land after 14 days aloft". GizMag. Retrieved 4 December 2012.
- Amos, Jonathan (2010-07-17). "Zephyr solar plane flies 7 days non-stop". BBC News. Retrieved 2010-07-17.
- Amos, Jonathan (2010-07-14). "Zephyr solar plane set for record endurance flight". BBC News. Retrieved 2010-07-14.
- Amos, Jonathan (2008-08-24). "Solar plane makes record flight". BBC News (in BBC). Retrieved 2008-08-25.
- QinetiQ Group PLC (14 Sep 2008). "Zephyr - QinetiQ High-Altitude Long-Endurance (HALE) Unmanned Aerial Vehicle (UAVs)". Retrieved 2008-08-25.
- QinetiQ Group PLC (16 July 2010). "QinetiQ’s Zephyr solar powered unmanned aircraft soars to new world records". Retrieved 2010-08-17.
- Bush, Steve (28 September 2007). "Inside Qinetiq's Zephyr solar powered plane". Electronics weekly. Retrieved 4 December 2012.
- Goodier, Rob (7 July 2010). "Solar Plane Aims for New Record: 3 Months Aloft Without a Pilot or Fuel Read more: QinetiQ's Zephyr Solar Powered High Altitude Plane - Solar Powered UAV Plane Record - Popular Mechanics". Popular mechanics. Retrieved 4 December 2012.
- Tovey, Alan (31 August 2014). "Fly 11 days non-stop? Now that's long-haul". Daily Telegraph.
- "Wing-to-tail guide to Zephyr, the 'eternal' plane". BBC News. 23 July 2010.