The inflatable struts of a strut kite are typically made of lightweight materials, such as plastic or PVC, and are filled with air using a pump. The struts are attached to the leading edge and the trailing edge of the kite, which helps to maintain its shape and provide lift. The kite is controlled using a bar and lines, which allow the rider to adjust the angle of the kite and the amount of power it generates.
I assume you are referring to the "Strut Wing" or "strut-braced wing" configuration in aviation.
The strut-braced wing is a type of aircraft wing structure that uses struts to support the weight of the wing and distribute the aerodynamic forces to the fuselage. The struts connect the wing to the fuselage and act as load-bearing members that transfer the bending, torsion, and compression loads from the wing to the fuselage.