Operations of K-ships in tropical regions had shown a need for a blimp with greater volume to offset the loss of lift due to high ambient temperatures.

A contract was awarded to the Goodyear Aircraft Company for the prototype M-class blimp on August 16, 1943.

These airships were given the Navy designation of ZNP-M, (Z = lighter-than-air; N = non-rigid; P = patrol; M = type/class.)

These airships were powered by two Pratt & Whitney radial air-cooled engines.

Goodyear produced a final follow-on design, the N-class blimp, in the 1950s.