Air Berlin PLC (XTRA:AB1)'s NIKI Luftfahrt GmbH is gathering growing interest in the carrier from potential bidders. Sources told Reuters that International Consolidated Airlines Group, S.A. (LSE:IAG) was once again interested in Niki. Other interested parties include its founder and former Formula One champion Niki Lauda, Thomas Cook Group plc (LSE:TCG), PrivatAir S.A. and Ryanair Holdings plc (ISE:RY4C).

Niki's administrator said bidders have until Thursday to submit offers.