I just read somewhere that flyers can no longer use RCE when based...is this true?

Sort of... Fliers can still use ranged combat actions on figures in base contact with them, but they can no longer fire out of base contact.

So Supes can use RCE on Lex Luthor sitting next to him, but he can't fire on Darkseid who is sitting 5 or 6 squares away.

Finally! It only really makes sense after all, and we used it as a house rule anyways. Not fair that melee characters have to focus attention, but flyers can shoot someone else while they're getting pounded on. Heck, we don't even play that you can use RCE unless you're soaring if you're right next to a figure.