A US judge has dismissed a case alleging that a subsidiary of Boeing illegally helped the CIA fly terror suspects abroad on rendition flights.
ACLU brought the case on behalf of five men
The American Civil Liberties Union brought the case against Jeppesen Dataplan, saying it "falsified flight plans... to avoid public scrutiny".
But a San Francisco judge halted the case, as the CIA director had urged.
"The very subject matter of this case is a state secret," Judge James Ware wrote in a ruling.
CIA director Michael Hayden had earlier urged the judge to dismiss the case because he said that covert operations overseas could be exposed.
ACLU brought the case on behalf of five men who alleged the CIA had flown them to foreign prisons, where they were interrogated and tortured.
The plaintiffs were an Ethiopian living in the UK, an Italian working in Pakistan, an Egyptian citizen living in Sweden, a Yemeni, and an Iraqi who was a British resident.
The lawsuit against Jeppesen had claimed the services they provided were crucial to the flights.
However, Jeppesen had said it could not confirm if it was involved with the flights.
A report approved by a European Parliament committee last year said more than 1,000 covert CIA flights had crossed European airspace or stopped at European airports in the four years after the 9/11 attacks in 2001.
Jeppesen's participation allegedly included securing necessary landing and overflight permits for the flights between the US, Pakistan, Ireland, Cyprus, Morocco, and Afghanistan.