WASHINGTON -- Airbus SAS on Friday asked a U.S. court to remove Boeing Co. lawyers from World Trade Organization deliberations on aircraft subsidies, saying one of the partners in Boeing's law firm has inside knowledge of Airbus strategy.

Marco Bronckers, a partner in the Brussels office of Wilmer Cutler Pickering Hale and Dorr LLP, used to be an Airbus lawyer, according to the firm's motion in the Superior Court of the District of Columbia.

This gives him inside knowledge of Airbus strategy, which is a conflict of interest under D.C. bar rules, the Toulouse, France-based plane manufacturer said.

Airbus spokesman Clay McConnell said the lawyer had a key role developing Airbus strategy for the WTO battle, which involves dueling European Union and U.S. complaints.

The U.S. wants to block subsidized development loans to Airbus from European governments, while the E.U. seeks curbs on indirect aid to Chicago-based Boeing through tax breaks and research contracts.

"That is an extreme breach of confidentiality and ethics rules on the part of this lawyer," McConnell said. "The law firm has an ill-gotten copy of the Airbus playbook."

The law firm, known as Wilmer Hale for short, said the Airbus claims aren't justified.

"While we have not yet seen the court papers, we are familiar with the matter, which as reported concerns work done by a partner when at another law firm more than 15 years ago. There has been no breach of any ethical obligations by our firm, and we intend to oppose the motion vigorously," said Bill Perlstein, the firm's co-managing partner.

A Boeing spokesman confirmed that the company has hired Wilmer Hale for WTO-related work but declined to comment further.