Travelers navigating through a busy airport have become accustomed to a hectic juggle of IDs and boarding passes while lugging bags through security checkpoints and boarding.Some airlines recently have been gradually adding technology to streamline the process and replace IDs and boarding passes with fingerprints and facial scans.Atlanta-based Delta Air Lines’ latest move along the biometrics path is allowing members of its Sky Club airport lounges to enter using their fingerprints instead of a membership card or boarding pass.As more people become accustomed to using their fingerprints or faces to use their smartphones, travelers also have become inured to the spread of biometrics in the airport.But some privacy advocates warn that convenience could mask the risks of a world where security depends on fingerprints and facial scans.Some passengers already have been using biometrics to identify themselves at the airport.