This aircraft was a conversion of the Navy's Curtiss F5L patrol flying boat. Thank you to Mark Lincoln for that additional information.

Each Aeromarine Model 75 was a conversion of a Curtiss F5L or Curtiss H16 maritime patrol aircraft originally built for the U. S. Navy. As war surplus, these aircraft were bought and remodeled, some in the company's own workshops.

Aeromarine Airways was first known as "Aeromarine West Indies Airways" when founded in 1920. In the spring of 1921 the airline was reorganized with Inglis Moore Uppercu, who had the franchise for Cadillacs in New York City, as its president. Aeromarine Airways established many firsts during its existence:

The first U. S. International Air Mail Service
The first Scheduled U. S. International Passenger Service (Key West to Havana, November 1, 1920)
The first Total-Service U. S. Airline (Passenger, U. S. Mail and Express Cargo)
The first In-flight movie (Chicago, August 1921)
The first Airline Baggage Label (1921)
The first U. S. Airline ticket office (Cleveland, July 1922).

Aeromarine's slogan was "Speed Safety Comfort". Their overseas flights in seaplanes named the Nina, Pinta, and Santa Maria brought passengers to popular destinations that still allowed drinking at the start of Prohibition. In 1924 they introduced the Aeromarine AMC Model, a 6-passenger new metal-hulled, six-passenger aircraft into service but it only operated a short period of time before Aeromarine ceased operations due to lack of money.