They're from Pilots for 911 Truth. (The guys who might know what they're talking about.)
The first video shows that the reported 500 knot sea-level airspeed of Flight 175 was nigh impossible, if not perfectly theoretically impossible.
The second video has a few radio interviews with professionals pilots, including one who captained Flight 175 itself. He indicates that there is no way anyone flew a 767 into such a small target at five hundred knots.
We already know that what struck the South Tower was not Flight 175, due to the JT9D-7 series engine on Murray Street. But a watching of these videos will confirm on an emotional level what we already knew on a technical level. When professional pilots with tens of thousands of hours of airtime on the class of aircraft in question say, "Oh yeah, that didn't happen," and when you've got a 747 engine on Murray Street, then you really know it didn't happen.
And since we've got an E-4B Command and Control aircraft just leaning up against a lamppost and cleaning its nails and whistling as planes happen to fly into the Twin Towers, I know that that E-4B piloted those drones in. So just for fun, just so that we can put our case together, it would be useful to research that Cooling Duct Assembly and see what military engines that assembly was used on. The goal is to pin it down to a particular aircraft, if possible. Whatever it was, it would have to be reinforced to withstand the pressure of sea-level air density at 500 knots.