In the late 1950s the US Navy experimented with the concept of aircraft carrying submarines armed with jet fighters. Several submarines capable of carrying aircraft-sized cruise missiles had been built as a stop-gap and contingency to ballistic missile submarines: converted fleet boats USS Tunny and Barbero were fitted with external hangars on the aft deck for trials, each carrying two Regulus-I missiles.
These were followed by two diesel-electric cruise missile submarines of the Grayback Class were put into service, each with four missiles, and one submarine of the Halibut Class with five missiles. If these boats could carry such large missiles, then the US Navy supposed that they could alternatively carry manned aircraft.
Initially the idea was to built aircraft which could be launched from the existing boats, but soon the larger purpose-designed AN-1 concept was born. Based on the Halibut Class, the AN-1 would carry eight fighters. The aircraft would be a tail-sitting Vertical Take-Off and Landing (VTOL) design with the same overall size footprint as the Regulus-II missile. The aircraft would be carried in two internal hangers similar to those on USS Halibut, and rolled out of the hanger to vertical launch positions while the boat is surfaced. The launch boosters would be carried in separate smaller hangers and mated with the aircraft on the launch rail. Four aircraft could be launched in under 6 minutes, or all eight in under 8 minutes.