Moving from tethered to free-flying LTA systems, Lockheed Martin is building the Hale-D (High Altitude Long Endurance - Demonstrator) under US Army funding. Scheduled to leave the ground in August 2009, the Hale-D is designed for a 15-day endurance with a 23-kg payload, and is to prove that an airship can operate at 60,000 ft. It may pave the way for the Lockheed Martin HAA (High Altitude Airship) project, a concept originated by the US Missile Defense Agency (MDA) with the eventual aim of a vehicle staying aloft for several months at 65,000 ft with a 900 kg sensor payload. The Darpa Isis (Integrated Sensor Is Structure) programme envisages a solarpowered airship that would remain on station for up to ten years at around 70,000 ft, extending the radar horizon to 600 km. Isis would carry a UHF/X-band radar with a massive Aesa bonded to the inner side of the envelope. The concept exploits the fact that increasing antenna size reduces the emission power required, but (to succeed) demands breakthroughs in all component weights. In April Lockheed Martin was selected to build a onethird scale demonstrator, which is expected to remain on station for 90 days. On a more modest scale, in 2008 US Naval Air Systems Command issued an RFI (request for information) relating to an LTA drone capable of a seven-day loiter at 20,000 ft altitude and 9250 km radius with an 1130-kg payload.

One of the technology building-blocks for hale (high altitude, long endurance) drones is the US Air Force Research Laboratory Sensorcraft reconnaissance concept, aimed at achieving an endurance of 40 hours at 60,000 ft and an operational radius of 3700 km. Boeing, Lockheed Martin and Northrop Grumman are all undertaking Sensorcraft studies.