Canada's major airlines say they will be forced either to break privacy laws or to ignore new American air security rules unless the federal government comes up with a response to U.S. demands for passenger information.
The National Airlines Council of Canada, which represents the four largest Canadian carriers, is pleading with the government to find "a permanent solution" to the dilemma posed by the U.S. Secure Flight program.
The program would collect the name, gender and birth date of the approximately five million Canadians who fly through American airspace en route to destinations such as the Caribbean, Mexico and South America, even if their planes don't touch the ground in the States.
The U.S. Transportation Security Administration (TSA) would then vet the names against security watch lists.
Passengers whose names appear on the list could face anything from extra security screening to being barred from a flight. There are also concerns the personal data could be used for purposes unrelated to aviation security.
Washington is still reeling from an apparent attempt by a Nigerian man to blow up a jetliner over Michigan by igniting explosives sewn into his clothes.
The near-disaster has put renewed pressure on the TSA to ensure the skies are safe.
Canadian airlines have already begun passing along the personal information for flights that land in the United States.
But the requirement to hand over information for international flights over U.S. airspace was put on hold last February pending discussions with the governments of Canada, Mexico and some Caribbean countries.
In a November letter to Bill Baker, deputy minister of Public Safety, the National Airlines Council says Canadian carriers "are not aware of any progress" on the discussions and are concerned the TSA might suddenly enact the overflight provisions.
The council says this would force Canadian airlines to breach either Secure Flight or the Personal Information Protection and Electronic Documents Act, a federal privacy law that applies to Canadian companies.
An internal Public Safety document prepared last January agrees that sharing such information is "currently prohibited" under the privacy law.
Nicole Baer, a spokeswoman for the federal privacy commissioner, said it was too early to determine whether giving overflight data to the Americans would break Canadian privacy law.
The Public Safety document, obtained under the Access to Information Act, raises other concerns about Secure Flight.
"It is possible that Canadians overflying the United States could be denied boarding based on U.S. no-fly lists that were developed based on lower U.S. risk tolerance," says the January, 2009, assessment.
"There are also no guarantees how the U.S. will use the information it obtains from carriers overflying its territory."
The United States has indicated it will waive the Secure Flight requirement to provide information for overflights if Canada creates an equivalent security screening system.
Last March, the airlines council told Public Safety Minister Peter Van Loan in a letter that application of U.S. Secure Flight rules in Canada "is a direct result of the failure to ensure" that Canada's no-fly list, known as Passenger Protect, is "an accepted part of a continental aviation security system."
The airlines council favours a homegrown system as long as carriers don't bear any new costs.
Canada has been working for years on a more comprehensive passenger screening system. The Public Safety Department had no immediate update on those plans.
Critics say extending the Secure Flight program to Canadian flights that merely pass over the U.S. would indeed be a threat to Canadian sovereignty.
The Ottawa-based International Civil Liberties Monitoring Group has argued that sprawling American watch lists could ensnare many Canadians - or activists, immigrants and refugees who want to fly to Canada from Latin America but must travel through American airspace to do so.
Washington says Secure Flight, which transfers the task of watch-list screening to the TSA from individual airlines, will reduce the number of false matches - a longstanding problem with common names - and clear up mistakes more quickly.