SAN FRANCISCO - OCTOBER 17:  Clear agents wait to assist passengers with the Clear express security lane October 17, 2007 at San Francisco International Airport in San Francisco, California. San Francisco International airport is the ninth airport in the U.S. to to offer the express security lanes which have attracted over 6,000 travelers at San Francisco International to sign up for the service which costs $99 per year and allows you to bypass long security lines. Getty Images logo Getty Images 20 months ago

SAN FRANCISCO - OCTOBER 17: Clear agents wait to assist passengers with the Clear express security lane October 17, 2007 at San Francisco International Airport in San Francisco, California. San Francisco International airport is the ninth airport in the U.S. to to offer the express security lanes which have attracted over 6,000 travelers at San Francisco International to sign up for the service which costs $99 per year and allows you to bypass long security lines.