Full-body scanners are being introduced at Stewart International Airport. Air travelers will now have to step into a machine and get a body scan before boarding a plane. "This is not an X-ray like earlier imaging machines," says Gregory Sitler, of the Transportation Security Administration (TSA). "It shows a generic outline of a person instead of the actual passenger, and highlights any anomalies that need to be check out." The TSA says it'll be training security personnel on how to properly use the new full-body scanners until Dec. 5, when they'll start using them full time.