X-44 Manta: What the New NGAD Fighter Could Eventually Look Like

The Air Force’s—and NASA’s—motivation behind the X-44 Manta project, starting in 1999, was to test the feasibility of full yaw, pitch and roll authority without tailplanes (horizontal or vertical), with attitude control relying purely on 3D thrust vectoring.

The Air Force Is Only Building One NGAD: Secret Sixth-Gen Fighter

Fighter of Discord: Is the Euro-Six Alive?

X-44 MANTA The National Interest

X-44 Manta: Is This What America's 6th Generation Fighter Will Look Like? - 19FortyFive

Lockheed Martin X-44 MANTA (Multi-Axis, No-Tail Aircraft) Tailless Combat Fighter Technology Demonstrator Proposal

Aviation, Page 5

What are properties of the Raptor that would make it better? - Quora

The National Interest: Blog

The National Interest: Blog