Will Return to Duty get someone out of the Brig?
No, the rules are fairly explict about getting out of the Brig.


  Players may move out of “Sickbay” without difficulty, but not the “Brig.” They may only move out of the “Brig” by passing the skill check listed on the location.


Piloting Vipers


  A player who wants his character to pilot a viper simply moves his character to the “Hangar Deck” location and uses the action listed there.


Also from the BSG Errata, although it doesn't mention your particular example, it is a similar move a character from the Brig to some other location.


  Q: If a character is in the “Brig,” and a card sends him to “Sickbay,” is he moved from the “Brig?”
  A: No. This reflects a change from previous rulings.