Two senators said Wednesday they want to know how many airlines have given passenger information to the government, a request that follows last week's disclosure that American Airlines provided such data.
Sen. Susan Collins and Joseph Lieberman are asking the Homeland Security Department to identify the carriers whose passenger information the government sought.
They have asked Asa Hutchinson, undersecretary for border and transportation security, to explain why the department asked American for the data, how it used the information and why federal privacy laws were not broken.
Collins, R-Maine, heads the Senate Governmental Affairs Committee, which oversees the department; Lieberman, D-Conn., is the committee's top Democrat.
In September, privacy activists disclosed that JetBlue had turned over 5 million passenger records to a government defense contractor. Northwest Airlines later acknowledged it gave passenger data to the National Aeronautics and Space Administration.
Last week, American said it had given such records to the government, at the request of the Transportation Security Administration for use by four of its potential contractors.
The airlines are facing class-action lawsuits. The disclosures have raised more privacy concerns, which have delayed a program intended to keep potential terrorists off flights.
Calls to Hutchinson's office were not immediately returned Wednesday.
The agency says it needs the passenger records to test the program, a computerized system of background checks for airline passengers. Some critics say the project has the potential to violate the privacy rights of many travelers.
The airline industry will not voluntarily turn over passenger data such as name, address, travel history, meal preference. The transportation agency says that is delaying the screening project and that airlines may be ordered to supply the information.
The senators said American's disclosure suggested that the government was more directly involved in the use of personal information about passengers than previously known.
They wrote that it appears the government requested the records "for its own research purposes rather than merely requesting that data be provided to another agency, as occurred in the JetBlue matter."
Collins and Lieberman also said American's announcement also raised questions about some of the transportation agency's public statements.
The agency told reporters, lawmakers and the congressional investigators that it had used only 32 simulated passenger records to test the system, Collins and Lieberman noted.
"American Airlines has now indicated that it provided over 1 million passenger itineraries at TSA's request," the senators wrote.