The researchers at Natick are also working on portable buildings that are made of what are essentially large,high-strength textile balloons. Called air beams,these buildinh materials would allow ateam to build a structure large enough to hold airplanes in a fraction of the time a conventional metal structure would take. The largest air beams,about 0.75 meters in diameter and 24 meters long,are so rigid that you can hang aheavy truck. Yet they can be packed into a truck. Ehereas a conventional metal hangar takes ten people five days to set up,one made of air beams can be set up by six people in just two days.