[4] After 26 games with the Monsters, Aittokallio received his first NHL recall to the Avalanche during the lockout shortened 2012–13 season, to fill the back-up position after an injury to starting goaltender Semyon Varlamov on 9 April 2013.

[7] In the 2014–15 season, Aittokallio suffered from injury and indifferent form, playing with the Monsters and the Fort Wayne Komets of the ECHL.

Despite being tendered a qualifying offer by the Avalanche, Aittokallio opted to return to Finland to further his development in signing a two-year contract with Liiga club, Oulun Kärpät on 2 July 2015.

[12] Following two seasons with Ässät, Aittokallio left the Liiga, in signing a one-year deal with newly promoted German club, Bietigheim Steelers of the DEL, on 5 July 2021.

[14] He made 1 appearance with JYP before the conclusion of his trial contract and was later signed for the remainder of the season with Slovak Extraliga club, HK Nitra, on 13 November 2023.

[17] Touted for his hockey intelligence, good reflexes and athleticism, Aittokallio was selected to be first choice goaltender for Finland at the 2010 World Under-18 Championships in Minsk, Belarus.