Material FIberglass is one type of fiber composite material that has the advantage of being strong but still light. Although not as stiff and light as carbon fiber, fiberglass is more resilient and relatively cheaper on the market. Fiberglass sheets are commonly used for making aircraft, boats, car bodies or interiors, bathroom fittings, swimming pools, septic tanks, water tanks, roofs, piping, insulating walls, surfboards, trash cans and others.