For those still interested, here's what Sheldon Brown's website had to say about the history of Aero Bars:

"Æro bars originated from an attempt to duplicate the "tuck" of a downhill skiier. They first appeared in 1986 when Pete Penseyres introduced them in the Race Across America (RAAM).

Although they were an instant hit with triathletes and time-trialists, professional racers were slow to accept this innovation. When Greg Lemond rode Scott æro clip-ons to victory in the decisive final time trial of the 1989 Tour de France, the ice was broken, and few racers will now ride time-trial stages without them. Although æro bars originated as racing equipment, and are particularly associated with triathlons, they have also become quite popular with touring cyclists and randonneurs, as much for the relief that they give to the hands and wrists as for their ærodynamic qualities. "

I would somehow expect aerobars to have been developped independently by touring cyclists all over the place. It seems to me like it's a natural position to have if you're going to ride 8 hours a day for 2 months. Maybe the 1986 RAAM was the first time they made it to a greater event.