Aalborg AAL to Berlin BER flight with Norwegian Air

SAS, or Scandinavian Airlines, is the national airline of Denmark, Norway, and Sweden, headquartered in Solna, Sweden. Founded in 1946, it emerged from a merger of the three countries' national carriers to handle transatlantic operations. SAS operates extensive regional services within Scandinavia and Europe, as well as international flights to Asia and North America, with primary hubs in Copenhagen, Stockholm, and Oslo. As of July 2024, SAS, including its subsidiaries SAS Link and SAS Connect, operates a fleet of 133 aircraft to 130 destinations. SAS joined SkyTeam on September 1, 2024, after leaving Star Alliance.

Norwegian Air International (NAI) was an Irish airline and a fully integrated subsidiary of Norwegian Air Shuttle, operating under its corporate identity. Headquartered at Dublin Airport, NAI operated flights to destinations across Europe and the Middle East from various European bases. Between 2017 and 2019, it also offered services from Europe to the United States and Canada. NAI received its operating license and air operator's certificate from Ireland in February 2014, allowing it to leverage European Union airline freedoms. By April 2021, its aircraft and operations were gradually transferred to its Swedish sister airline, Norwegian Air Sweden, and its parent company.

CityJet is an Irish regional airline headquartered in Dublin, Ireland. Founded in 1992, it began operations in 1994, initially flying between Dublin and London City Airport under a franchise agreement with Virgin Atlantic. CityJet transitioned its business model in 2018, ceasing its own-brand scheduled services to focus on wet leasing aircraft to other European airlines. This means CityJet provides aircraft and crew to operate flights on behalf of other carriers. As of 2023, CityJet operates a fleet of Bombardier CRJ900 and CRJ1000 aircraft, primarily for airlines like Scandinavian Airlines (SAS), Lufthansa, and Brussels Airlines. In 2023, CityJet merged with Air Nostrum, forming the Strategic Alliance of Regional Airlines (SARA).

KLM Cityhopper is the regional airline subsidiary of KLM Royal Dutch Airlines, headquartered in Haarlemmermeer, Netherlands, and based at Amsterdam Airport Schiphol. Established in 1991 from the merger of NLM CityHopper and Netherlines, it operates scheduled European feeder services on behalf of KLM, connecting smaller cities and regional airports to KLM's main hub. As an affiliate of SkyTeam, KLM Cityhopper operates a fleet primarily consisting of Embraer E-Jet aircraft, including the Embraer 175, 190, and E195-E2 models. It serves numerous inter-European destinations, playing a vital role in KLM's regional and international network.