Inflated Membrane Structures on the Ground,in the Air and in Space 219 5 Interesting Combinations In order to optimize the structure further different principles might be coupled.For this three examples are given: The AirChain An interesting and efficient concept is obtained,if a number of high altitude balloons is coupled to a chain and covered by a aerodynamically smooth surface.The vehicle flies controlled by engines in each segment,see Fig.11. Fig.11.AirChain Stuttgart,Test Flight 1999 [11] Fig.12.Flying Roof,Munich 2000 [12]Inflated Membrane Structures on the Ground, in the Air and in Space 219 5 Interesting Combinations In order to optimize the structure further different principles might be coupled. For this three examples are given: The AirChain An interesting and efficient concept is obtained, if a number of high altitude balloons is coupled to a chain and covered by a aerodynamically smooth surface. The vehicle flies controlled by engines in each segment, see Fig. 11. Fig. 11. AirChain Stuttgart, Test Flight 1999 [11] Fig. 12. Flying Roof, Munich 2000 [12]