Can a talking, smiling simulacrum ever replace the real thing? Passengers traveling through Hall 40 of Orly Airport in Paris, France, can decide for themselves as they receive boarding information from holographic boarding agents. At the press of a button, the virtual agent is conjured seemingly out of thin air -- it's actually rear-projected onto a human shaped plexiglass board -- to greet passengers and inform them when to board their flight, and at which gate. The pilot program was launched last month, with the technology provided by the French marketing company L'Oeil Du Chat. Airport officials have reported a generally positive reaction to the 2-D avatars.