The exits at the Syracuse, N.Y., and Atlantic City, N.J., airports are designed to prevent passengers from backtracking into secure areas once they leave and to keep outsiders from entering through the exits.
Travelers step into a cylinder and wait as a door slides closed behind them. Another door then opens in front, allowing them to leave.
The doors could be the wave of things to come as the Transportation Security Administration prepares to shift exit-monitoring duties to local airports next year. Airports with the doors say it save them the cost of staffing exits with guards.