Documents show how Clear, which lets its members skip security lines at 35 US airports, is building a digital ID system for storing health care info and more (Dave Gershgorn/OneZero )

Dave Gershgorn / OneZero :
Documents show how Clear, which lets its members skip security lines at 35 US airports, is building a digital ID system for storing health care info and more  —  'You are your driver's license, your credit card, your health care card, your building access card'  —  In March, the air travel industry ground to a halt.