I think one of the reasons Pan Am went under is because they didn't have the domestic market to support their international flying. Hope DAL keeps that in mind. See comments below from another website.

Pan Am's founder, Juan Trippe, was the world's first airline tycoon, the imperial skygod, his company the aviation pioneer that came to be known as America's Imperial Airline. First to fly the Pacific, first across the Atlantic, first around the world—Pan Am was once one of the most glamorous and best-known global corporations. Its worldwide headquarters—the crown jewel—was on Manhattan's Park Avenue, the Pan Am Building, the world's largest corporate office building at the time. Pan Am had more international destinations than any other airline, flying to 113 cities in 81 countries, from Capetown to Moscow, Oslo to Buenos Aires. The other airlines at the time "were domestics, like Greyhound Bus," says Robert Gandt, author of the book Skygods: The Fall of Pan Am. Pan Am would have "no miserable lunches in places like Des Moines or Cincinnati or Boise. For them it would be sushi in Tokyo, petit déjeuner in Paris, tea in London."