Marquardt and GASL were heavily involved, as were General Dynamics, Republic, North American, Lockheed, and Douglas Aircraft.
Marquardt collaborated closely with GASL, merging for a time into a single company with Fern as vice-president.
It was a proposed flight engine that grew out of work at GASL, which had built small scramjets and tested them in wind tunnels.
Years later, Art Thomas still was miffed at GASL for this.
But his new facilities were far less extensive than those he had used at GASL, and his opportunities were correspondingly reduced.
He wanted to build a larger version of this backyard engine and to test it at GASL, but even this seemed out of reach.