Mr. Dicks argued that it would be “inconceivable” for the Air Force to reopen the bidding without considering the W.T.O. panel’s findings. “The U.S. government cannot reward illegal market actions that have harmed U.S. manufacturers and stolen U.S. aerospace jobs,” he said in a statement.

Image An Airbus A380 from Singapore Airlines. Credit... Mike Clarke/Agence France-Presse — Getty Images

The United States had also claimed that Airbus received about $8 billion in research and development and facilities financing. Congressional aides in Washington said that the United States had won some  though not all  of those points as well.

Both Airbus and Boeing have about six weeks to review the finding and comment on it. The trade body is expected to issue a formal ruling by the end of the year. Both sides can appeal that ruling, but W.T.O. rules limit the process to 90 days, making a final outcome likely in the spring.

European officials who had been briefed on the report said that the W.T.O. panel had rejected 70 percent of the claims in the American complaint.

“Reimbursable investment loans for the A380 were not judged to be prohibited in their totality,” said one person with knowledge of the report.

American officials who had been briefed on the ruling disputed that the United States had lost on that many points. In some cases, they said, only one of the various arguments needed to be accepted for the panel to find that some subsidies were unfair.