Charlie Sheen & Brooke Mueller Flying HIGH Again ... On a Private Jet

8/19/2011 3:45 PM PDT

Charlie Sheen and Brooke Mueller -- Reunited and Flying High

Charlie Sheen and Brooke Mueller boarded a private jet ... together in Los Angeles Friday -- proving just about everything can change in just 3 months.

As TMZ first reported, Charlie's been very involved in Brooke's drug rehab -- enlisting his own team of doctors for her treatment.

It's unknown where they jetted off to today -- but this is the best Brooke has looked since her divorce from Charlie was finalized back in May.