Every day, about 600 transatlantic flights carry thousands of passengers safely between continents, high above one of the most dangerous stretches of ocean. It’s doubtful if more than a few give a thought to those who pioneered the routes, in primitive flying machines powered by unreliable engines. For many, it proved a leap too far. This month marks the eightieth anniversary of one of those remarkable flights, now almost forgotten, that proliferated in the 1930s as aviation came of age. Daring flyers chased fame, records, sometimes prizes, their brave exploits uplifting the mood of a depressed world and promising a…