At 1:40 he mentions the "Hermes project." The V-2 wasn't part of that. That was initially a project given to General Electric to develop a SAM based on the German Wasserfall as a competitor to the Bell / Douglas Aircraft Nike missile program.
As it turned out, the Wasserfall was a pretty crappy missile and after half a dozen launches it was relegated to research and then abandoned. GE's Hermes program then became a more generalized R & D effort with the SAM development left to Bell and Douglas as the Nike was proving far more viable.
He's also wrong on the V-2 being the basis for most US ballistic missile development. That honor goes to Convair's MX-774 Hiroc. The V-2 instead was relegated to being a cheap and available missile for general R & D but was hardly seen as still cutting edge by the late 40's. It would be, for example, Charlie Bossart's airframe design for the MX 774 that everybody copied and is still used today in large missiles and rockets abandoning the V-2 conventional aircraft airframe with the tanks and such installed within it to using the skin of the missile as the tank walls for fuel gaining rigidity through pressurization.