George Clooney & Jen Aniston TOGETHER!!!

6/28/2012 8:00 AM PDT

George Clooney and Jen Aniston -- TOGETHER ... on a Private Jet

What happens in Switzerland, doesn't stay in Switzerland ... especially when George Clooney and Jennifer Aniston get on a private plane ... TOGETHER!

It all went down at the Lugano Airport, where Clooney and his GF Stacy Keibler boarded a fancy private jet ... followed by Jen and her BF Justin Theroux.

Pretty shocking ... considering we haven't seen Cloon and Aniston in the same place since Jen divorced George's BFF Brad Pitt ... back in 2005.

Since Clooney and Pitt are tight, it could be a sign Brad and Jen have buried the hatchet. On the other hand it may have nothing to do with that at all.