Pan American World Airways, hit hard by Americans canceling trips to Europe and the Mediterranean because of fear of terrorism, is laying off 212 telephone reservations clerks and removing two European routes from its schedule, a company spokesman said yesterday.

The layoffs of clerks, including 69 in its Washington reservations office, are "entirely driven by the drop in telephone reservations calls," Pan Am spokesman Alan Loflin said.

Asked whether layoffs of pilots, flight attendants or other Pan Am employes were anticipated, Loflin said that all areas would be examined closely. "It's obvious that if this situation continues, there may be further manpower reductions. . . . It depends on how long this reaction to terrorism lasts."

Pan Am also is switching two of its trans-Atlantic routes to domestic flights. Routes from Chicago to Frankfurt and from San Francisco/Los Angeles to Paris are being removed from the schedule, Loflin said. They will be replaced with flights between Los Angeles and New York and between San Franciso and New York City.

Loflin said those changes had been considered before the Libyan situation because bookings on the flights had been low.

Airline analysts have said that Pan Am and Trans World Airlines, the two U.S. carriers with the largest number of North Atlantic flights, could be severely damaged by the reluctance of Americans to travel in Europe this summer.

Some travel experts have estimated that travel to Europe and the Mediterranean could be down by as much as 80 percent this year.