GENEVA (AP) -- The World Trade Organization set up panels Wednesday to investigate allegedly illegal subsidies paid by the EU and U.S. to airplane makers Airbus and Boeing Co., although both sides say they are still willing to try to reach a negotiated settlement.
The creation of the panels restarts what could become the costliest and highest-profile case in the 10-year history of the WTO and one that could result in higher ticket prices for plane travelers.
''This case will be the most complicated case that the WTO has ever handled,'' Fabian Delcros, an EU spokesman in Geneva, told The Associated Press. ''But the communication channels remain open.''
The United States also would prefer to reach a settlement and is ''prepared to negotiate in parallel with (its) WTO case,'' Richard Mills, spokesman for U.S. Trade Representative Robert Portman, told the AP.
The WTO's dispute settlement body agreed to set up the panels after the United States and European Union both went forward with a second request, a month after each side blocked one another in routine bureaucratic maneuvering.
Washington filed a complaint at the 148-member global trade body in May about plans for European government aid to fund the development of Airbus's A350 _ a mid-sized jet aimed at competing with Boeing's 787 Dreamliner. Airbus is a joint venture of Netherlands-based EADS NV, with an 80 percent stake, and U.K.-based BAE Systems PLC, which owns 20 percent.
The EU then filed a counter-complaint, claiming that Chicago-based Boeing continues to benefit from massive subsidies in violation of international trade agreements.
The U.S. has argued that Airbus has used massive amounts of EU and member state subsidies to seize more than half of the world's civil aircraft market at the expense of Boeing.
''We are going to the WTO because we want to see the end to launch aid and other new subsidies,'' Mills said.
Washington says it has been seeking negotiations with the EU for over a year to end subsidies for civil aircraft.
The EU ''has only been willing to reduce subsidies, not end them,'' the United States said in a statement to the dispute settlement body. ''Even now, certain (EU) member states are insisting on providing new subsidies to Airbus that Airbus says it does not even need.''
But the EU argued that it has been Boeing that has distorted the civil aircraft market, and dismissed U.S. claims of illegal European support for Airbus as ''purely speculative.''
''This procedure will clearly show how massively Boeing is being subsidized,'' said trade official Raimund Raith, who represented the EU at the meeting of the dispute settlement body.
The EU ''has made genuine attempts to settle the case amicably instead of pursuing the path of litigation,'' Raith said. ''Unfortunately the U.S. was not prepared to move an inch.''
The EU and United States now must now decide on three to five arbitrators for each panel. Once that has been agreed on, in theory the panels will have nine months to produce their findings, although the case is expected to last much longer.
EU Trade Commissioner Peter Mandelson has said it could take ''years to resolve'' the standoff but it would likely result in a legal stalemate.
The complaints reactivated a legal process at the WTO that was frozen when the EU and the U.S. entered negotiations at the beginning of the year.
Without government financing, both Airbus and Boeing would be forced to cut back on new cost-saving technologies and new planes, analysts have said.
Airbus spokeswoman Barbara Kracht declined to comment, saying it was a matter for the European Commission to handle. Boeing did not immediately issue a comment.
Shares of Boeing fell 4 cents to $64.85 in midday trading on the New York Stock Exchange.
