The “arm” touching the bus is made of carbon fiber. The shirt and vest is hiding a sophisticated harness, and his real right arm.
So how did he walk across the Thames? Invisible pontoons is my guess...
How does he get into and out of said harness with people watching?
Or did he just appear from around a corner already hanging there and then disappear around another corner to “unload”?
No, I don’t believe he can levitate, I just want to know how he started and ended the trick.