Aas' work in sculpture spanned several different styles and material bases. His most famous work, a statue of King Haakon VII, located in the June 7 Plaza, is made of clay and plaster and cast in bronze. A statue of Henrik Ibsen in Bergen is made of granite, while several other public decorative works are made in wood. His 10-ton heavy wall decoration "Nordisk Lys" in the Council of Europe's Council of Ministers building in Strasbourg is made of laminated spruce. It is 16 meters wide and 6 meters high.