The computer age is on the horizon, and American Airlines has a secret weapon: SABRE. Sure, the airline is top of the heap under the current pen-and-paper reservation system — the one where travel agents use a massive phonebook to look up flights, then call individual airlines to book a ticket. But they’re tired of playing phone tag. The American Society of Travel Agents has plans to roll out a new electronic system, one that could force American to lose its unofficial preferred status. The company has to get its system to market first — and its leaders have to convince the travel agencies to get onboard.