On 9 January 2004, Niki announced cooperation with Air Berlin. In late 2011, Niki merged completely with Air Berlin, sharing operations, booking systems, and aircraft. On 20 March 2012, Niki became an "affiliate member" of Oneworld as a subsidiary company of Air Berlin. Starting in late 2012, Niki successively repainted their aircraft in the Air Berlin paint scheme, using the Niki logo only at the nose. The new paint scheme was applied during regular C checks.
