That...actually looks suspiciously like the Scaled Composites Stratolaunch superlifter. Stats line up pretty well too, Stratolaunch sits at 375 tons gross without payload, though being two 747-400s strapped together Stratolaunch would considerably up that passenger count.
Also I just learned Stratolaunch has been cancelled and sold off to the [EXPLETIVE REDACTED] sleazebags who ran Chrysler and Remington into the ground. My disappointment is immeasurable and my day is ruined.