4 Types of Airframe Construction:

1. Truss with canvas 

2. Truss with corrugate plate 

3. Monocoque construction 

4. Semi-monocoque construction

During the past century, techniques for constructing airframes evolved from the wooden truss structure employed in the early Wright Flyer to monocoque plywood shells to the semi-monocoque shells used in all metal aircraft. Truss structures utilize a framework of interconnected tubes called longerons that are braced with vertical and horizontal struts. The main disadvantages of this type of structure are excess weight and lack of streamlining. In monocoque construction the exterior surface of the fuselage is also the primary load-bearing structure. This technique offers considerable strength as well as good streamlining, but dents or surface deformations can compromise structural integrity. Picture a thin-walled aluminum can that is able to withstand considerable force applied to the ends, but collapses when a dent is made in the side. Semi-monocoque designs utilize bulkheads and formers  that are connected by horizontal stringers. This internal framework helps to support loads together with a rigid skin made of aluminum or fiberglass.