The Star Alliance is seeking "legal and regulatory clarification" of the recent content sharing deal between leading GDSs Sabre and Amadeus.
Alliance ceo Jaan Albrecht said he was "surprised" the two GDSs were "allowed to co-operate in such a manner in a market which already lacks any real competition."
He added: "We fully support our members in seeking legal and regulatory advice as well as clarification of the practical implications of this announcement and continue to press ahead with our already commenced ACAP project."
Under the ACAP project (Alternative Content Access Platform), the 18-strong Alliance
has signed deals with two so called GNEs, G2 Switchworks and ITA Software as part of its drive to shave $2bn from its annual GDS costs.
It is also working with Lufthansa Systems to develop a common IT platform for all its members.
Under the Sabre-Amadeus deal, the two GDSs can use the other to complete bookings if an airline is refusing to work with one of them. The deal has already been criticised by airlines including American.
BA expands e-ticket links
BA has signed an agreement with GDS and IT provider Amadeus to expand its e-ticket interlining with 80 new partners over the next two years.
In a separate move, the airline has also completed its migration to Amadeus Codeshare which will enable it to facilitate and develop its codesharing with its ten oneworld partners as well as KLM and SN Brussels.
Commenting on the interlining agreement, Jerry Foran, BA's product delivery manager, said: "These new interline links will allow us to grow the number of routes on which our customers can travel using an e-ticket and help British Airways advance towards the 100% e-ticket target set by IATA for the end of 2007."
Open Skies plan hit snag
The EU is still hopeful of an Open Skies agreement with America this year despite an apparent easing of American plans on foreign ownership of airlines.
The plans were eased by the Bush administration after opposition form Congress which has fears over national security and the economy if foreign interests have too high a stake in US carriers.
The agreed aviation aspects of the Open Skies deal are not likely to be signed if the EU is not happy with the changes in US ownerships rules.
But an EU spokesman said that the matter was in the hands of the US.