Airlines sued the CIA and the FBI on Tuesday, asking a US court for access to information they say would likely show that they acted reasonably on the day of the September 11, 2001 terrorist attacks. The two lawsuits in US District Court in Manhattan were filed as aviation companies build their defenses against lawsuits seeking billions of dollars in damages for injuries, fatalities, property damage and business losses related to attacks. The aviation companies said the agencies had refused to let them depose two secret agents, including the 2001 head of the CIA's special Osama bin Laden unit, and six FBI agents with key information about al-Qaida and bin Laden. The airlines, airport authorities, security companies and an aircraft manufacturer said they were entitled to present evidence to show the terrorist attacks did not depend upon negligence by any aviation defendants and that there were other causes of the attacks. They said that the depositions were likely to result in evidence showing the terrorists were sophisticated, ideologically driven and well financed and would have succeeded regardless of any action by the aviation entities. "The aviation parties are entitled to show that operations conducted by the federal intelligence agencies were the most effective way to uncover and stop the Sept. 11 terrorist attacks and that the inability of the federal intelligence agencies to detect and stop the plot is a more causal circumstance of the terrorist attacks than any allegedly negligent conduct of the aviation parties," the FBI lawsuit said. In the CIA lawsuit, companies including American Airlines Inc., United Airlines Inc., US Airways Group Inc., Delta Air Lines Inc., Continental Airlines Inc. and The Boeing Co. asked to interview the deputy chief of the CIA's bin Laden unit in 2001 and an FBI special agent assigned to the unit at that time. The names of both are secret. In the FBI lawsuit, the companies asked to interview five former and current FBI employees who had participated in investigations of al-Qaida and al-Qaida operatives before and after Sept. 11. Those individuals included Coleen M. Rowley, the former top FBI lawyer in its Minneapolis office, who sent a scathing letter to FBI Director Robert S. Mueller in May 2002 complaining that a supervisor in Washington interfered with the Minnesota investigation of Zacarias Moussaoui weeks before the Sept. 11 attacks. The lawsuits also sought to speak to Harry Samit, an FBI agent in the Minneapolis office who was among those who arrested Moussaoui in August 2001. They said he had testified that he suggested to his superiors that the Federal Aviation Administration be notified that Moussaoui was involved in a plot to hijack a commercial airliner. The testimony was critical to their defense because both agencies play key roles in advising the FAA as to whether new security measures were needed to protect civil aviation against terrorists, the lawsuits said. The airline entities said they need the testimony to defend against accusations that they had primary responsibility to assess the threat posed by terrorists, that they should have detected terrorists' weapons, that they should have anticipated the attacks and that they should have identified and stopped the 19 terrorists who carried out the suicide hijackings. Requests to interview the agents were rejected as not sufficiently explained, burdensome or protected by investigative or attorney-client privilege, the lawsuits said. Government spokeswoman Yusill Scribner said she had no immediate comment on the lawsuits. FBI spokesman Richard Kolko said the agency had not reviewed the lawsuit against it and would not comment on pending litigation. A victims' compensation fund established by Congress has paid $6 billion (?4.35 billion) to 2,880 families of those who died in the attacks and more than $1 billion (?720 million) to 2,680 injured victims. But 41 cases filed on behalf of 42 victims remain pending in federal court in Manhattan because some victims decided to pursue the usual court route rather than accept payouts from the September 11th Victim Compensation Fund of 2001. The first trials to assess damages are scheduled to begin in September.