As you walk through the airport’s glass doors, your phone buzzes. You open the camera, hold it in front of you, and spin a slow 360 degrees. When you look at your phone screen, bright, translucent arrows overlay the ground in front of you, guiding you through the revolving doors and pointing you to the airport’s security checkpoint. As you move through the terminal, the digital arrows steer you down a corridor, onto a train, up an escalator, and finally to your gate, where your plane is almost ready to board.