Olympic Airlines (Greek: Ολυμπιακές Αερογραμμές, Olympiakés Aerogrammés – OA), formerly named Olympic Airways for at least four decades, was the flag carrier airline of Greece with their head office in Athens. They operated services to 37 domestic destinations and to 32 destinations world-wide. Their main base was at Athens International Airport, with hubs at Thessaloniki International Airport, "Macedonia", Heraklion International Airport, "Nikos Kazantzakis" and Rhodes International Airport, "Diagoras". Olympic Airlines also owned a base at London Heathrow International Airport. By December 2007, the airline employed about 8,500 staff.

Olympic Airlines was also accredited by IATA with the IOSA (IATA Operational Safety Audit) for their safety practices.

On 6 March 2009, the Greek State announced they had reached an agreement to sell the flight operations, ground handling operations and technical base of the group to Marfin Investment Group, the largest Greek investment fund, thus ending 35 years of state ownership.

On 29 September 2009 Olympic Airlines ceased all operations and most flights. Olympic Air, the new airline formed from privatisation, commenced flights. Olympic Airlines continued to operate some public service flights to Greek islands as well as some flights to destinations outside the European Union (Cairo, Alexandria, Tel Aviv, Beirut, Belgrade) until the Greek State conducted a public tender and redistributed the routes.

On 31 December 2009 Olympic Airlines ceased all operations, as flights to Greek islands have already been allocated and are being flown by other carriers and flights to destinations outside the European Union have been allocated to other carriers who started operating them from 1 January 2010. Until the final closure, Olympic Airlines used the temporary code OP for their flights (instead of OA, which is used by their successor, Olympic Air). All Olympic Airlines flights (using the OP code) since 29 September 2009 and until the final deadline of 31 December 2009, were operated by Olympic Air on a wet lease basis. The 31 December 2009 deadline as the final possible date that Olympic Airlines should cease operations, was agreed between the Greek Government and the European Commission as part of the deal to close Olympic Airlines and sell the name and assets to Olympic Air. It was initially expected that operations would end much earlier, but due to the change of government in October 2009 the public tenders for the reallocation of subsidised flights to the Greek islands and for international flight rights outside the European Union were postponed. The company stayed alive until the final deadline of 31 December 2009.

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