In sharing the shame and blame of the December 1991 demise of Pan American World Airways, some say that the company's long slide started with founder Juan Terry Trippe, viewed by many as arrogant in conducting business and who never planned for a qualified, long-term successor {letters, Jan. 21}. Others argue that the company's downfall came from more fundamental causes, such as poor management, deregulation, unions, apathy etc {letters, Jan. 4}.

I'd say that the end wasn't all that simple.

The U.S. government's refusal to allow Pan Am a connecting domestic-route network during the late 1940s -- at a time when domestic-based Trans World Airways and numerous blossoming foreign carriers were awarded international route authority over routes most of which Pan Am had pioneered -- started the beginning of the end.

Then came the era of repeated international terrorist attacks against U.S. policy overseas, often targeting Pan Am directly and culminating in the 1988 Clipper 103 disaster.

And last, when the threat of war in the Persian Gulf and a deepening recession caused airlines in general to suffer an acute burden of dropping traffic and months of soaring fuel prices, the U.S. Department of Transportation secretary suggested to the public that Pan Am might fold. Severely weakened, a great American institution did just that.

Considering the above, it's no wonder that, coupled with bad press, fear, a lack of travel agents and of public confidence, Pan Am's fate was sealed -- crushing at the same time the lives, hopes and dreams of thousands of hard-working Americans and many overseas employees of the Pan Am family.

So much for the loss of another traditional symbol of our pioneering spirit and heritage: a world-class trailblazer, goodwill ambassador, U.S. flag carrier and America's friend around the world.

Thanks, Pan Am, for you served us well -- through war, peace and 64 very proud years.

To you, a fond farewell. ROBERT J. BYRNE Amagansett, N.Y.