Share 'Chris & Rihanna -- Back Together'

TMZ reports: Rihanna and Chris Brown are both back in the city where she was beaten to a bloody pulp just weeks ago, and get this -- the twosome traveled to L.A. together! Further proof that their relationship is in fact "on-again," both Chris and RiRi were seen boarding a private jet together in Miami late last night (as seen above), and exiting the same plane together in Los Angeles early th…