Aas was specialized as speed skaters on the 1500 m. At the Olympic Winter Games in 1952 in the domestic Oslo he won over this distance in 2:21,6 min the bronze medal. Four years later, in Cortina d' Ampezzo, he could not place in the medals themselves. Over 1500 m, he finished in 10th place 2:12,9 min, about 5000 m in 8:01,6 min 6th place, but he was in the same year in Hamar is the only time in his career Norwegian national champion in speed skating. Later in the year he also won the Norwegian national championships in cycling on the road and on the track. For this success in several sports within a year he was awarded in 1956 the Egebergs Ærespris.
Also for international all-around championships carrion won several medals. In speed skating around World Cup 1958 in Helsinki, he managed to only medal win of his career at the World Championships. He took the bronze medal. Even with the speed skating all-around European Championships in 1957 and 1960 respectively in Oslo, he won the bronze medal both times.
His biggest success carrion at the Olympic Winter Games in 1960 in Squaw Valley. Together with the simultaneous Yevgeny Grishin he was in 2:10,4 min Olympic champion in the 1,500 m. In addition, he finished in 25th place in the 5,000 m and the 23 place in the 10,000 m.
Aas provided a total of nine track records.
After ending his sports career he worked as a warehouse manager for a toothbrush manufacturer. He died in February 2012.