Participating airlines expect media procurement costs to be cut by 'tens of millions of euros', according to Louise McKenven, Star Alliance's vice-president of loyalty and marketing.
All the airlines were clients of one of WPP's two media agencies, Mediaedge:cia and MindShare. The other carriers in the deal are ANA, Austrian, LOT Polish Airlines, Scandinavian Airlines and Spanair.
The proposal to group the budgets and take advantage of GroupM's volume buying power came after Star Alliance decided to review media buying for all its members in a bid to reduce costs.
Aside from volume discounts, the airlines will benefit from a media rewards programme, which offers credits for additional services such as market research and competitor tracking.
The deal is designed to allow flexibility for individual airlines. 'Some carriers are planning to test the waters with their pan-European media activity,' said Mark Davies, director of marketing communications for Star Alliance. 'Some are focusing on media spend outside their home markets, while others are aiming for media savings on a global scale.'
GroupM chief executive officer Irwin Gotlieb has assured the airlines that group buying will not compromise client confidentiality.
Other airlines in the Star Alliance, including Air Canada and bmi, may join the GroupM pact at a later date.
GroupM recently picked up HSBC's media business, part of a £350m account won by WPP agencies.