During the finale of XS season 1, Mala Mala Jong attacks a mountain on the outskirts of the Xiaolin Temple, which is located in China. Omi escapes with the Serpent's Tail, a Shen Gong Wu which turns the tangible intangible, by flying through the Earth to some nondescript American farmland.
This feat happens over 11 seconds of the episode. This is viable, considering the pace at which Mala Mala Jong advanced on them.
Now, I don't know how to find the exact distance Omi traveled, so I'll just consider it to be the radius of the Earth to be conservative.
6371000/11=579181.8m/s
or about mach 1703.5.
Several have matched the Serpent's Tail's flight speed, including Dojo. Omi outpaces Dojo in their race.
:tomato