The Department of Homeland Security launched test programs at the end of May at Hartsfield-Jackson Atlanta Airport and Detroit Metropolitan Wayne County Airport to scan the fingerprints of foreign nationals as they leave the country.

The DHS already collects fingerprints from arriving visitors under the US-Visit program, but needs to develop a system to check visitors as they depart, to verify that they have not overstayed their visas.

The 35-day test will try to determine whether the Transportation Security Administration or Customs and Border Protection should operate the checkpoints. Noticeably absent from the testing program are the airlines, which have been battling to stave off DHS attempts to make the carriers do the job as passengers check in.

Partly because of the airline complaints, Congress called for a DHS test.

US-Visit is a congressionally mandated program developed after the 9/11 terrorist attacks, but the DHS has fallen behind in implementation, according to a December report by the Government Accountability Office.

One source of delay has been the airline industry's resistance to previous attempts by DHS to incorporate the fingerprint check into the airlines' check-in process, at a time when airlines are trying to automate and simplify the process.

IATA estimated the airline cost at about $12.3 billion over 10 years, far more than the DHS had estimated. It said the DHS failed to account for the added costs for secure data transmission of the biometric data.

IATA said transmission requirements for biometric data would be between 350 and 800 times greater that what the airlines currently use for handling reservations data and related passenger information.

"Secure networks required for transmission of biometric data would need to be installed between the airports and the airlines' departure control systems because they currently do not exist," the GAO said.

Secure data warehouses for biometric data would need to be installed to store the data prior to transmission to DHS, the GAO said, with an estimated cost of about $1 billion to operate over 10 years.

Requiring the carriers to collect fingerprints would run counter to recent carrier efforts to use technology to streamline and speed up passenger processing, the GAO pointed out. "For example, most airlines and cruise ships allow passengers to confirm arrival and check-in online ... and print a boarding pass at a kiosk."