Could RFID technology be used to establish a virtual security line around an airport? I think the answer has to be "yes." Here is a report from late last year showing RFID automated vehicle identification (AVI) having been installed at Lima (Peru) International Airport to track concessionaire vehicles. According to the manufacturer (TagMaster), similar systems are now in use at San Francisco International Airport Monterey International Airport Jorge Chavez International Airport Bob Hope International Airport Sky Harbor International Airport Mesa Gateway International Airport Tucson International Airport RFID use in toll-booths is well-established, so much so that there is even a Wikipedia article on it. One could envision a TSA security plaza at the entrance to the airport itself combining the two technologies. Only thing I see stopping it would be the possible traffic mess.