The Clear program was designed to help frequent fliers get through airport security lines quicker by vetting their identities in advance. To sign up, customers had to submit to background checks and provide identifying information including Social Security and credit card numbers, current home address, date and place of birth, phone numbers and driver's license numbers, as well as having their fingerprints taken, iris images scanned, and digital images of their faces taken.

According to the Clear program's privacy notice, the company takes extensive measures to protect the data, including encryption of all personal information while it is in transit or storage. But VIP's abrupt discontinuance of Clear just days after it had been promoting the service as an ideal father's day gift and trying to get longer-term subscriptions for it, appears to have sparked considerable concern among customers.

Peggy Duncan, a personal productivity consultant and professional speaker based in Atlanta, said she learned about the company's demise via a brief e-mail sent to her in the early hours on Monday morning. Despite having only positive experiences with the service so far, she said today she is very worried about her personally identifiable data held by Clear.

"They have everything. They have all my fingerprints, they have [data on] the iris of my eyes," Duncan said. She signed up for the service at Atlanta airport and didn't mind handing over all of the personal information because "I figured they'd have had to go through a lot of vetting to be even connected with a service that allows people to get on a plane."

At this point, all she wants is for the data to be destroyed, now that the Clear program has become defunct, she said. "I would like to understand their process for destroying all of the personal data they collected and have someone from a government agency verify that they have done that," Duncan said.