American Airlines and Pan American World Airways entered into a route exchange agreement which, when approved in mid-1975, enabled American Airlines to serve Bermuda, the Dominican Republic and Barbados from New York as well as Bermuda from Boston, all formerly Pan American segments under Foreign Air Mail Routes 5 and 18. In return, American Airlines gave Pan Am its South Pacific route (then defunct for some time due to unprofitability).
On November 1, 1975 the cacheted United Nations covers intended for the first flight to Barbados were mistakenly put into the mails instead of being boarded on the inaugural flight.