Above, "Barber Bob" was originally called Ball of Fire while in service with the 328th in North Africa
Used up and worn out B17's and 24's were brightly painted with group-specific high-contrast patterns in stripes, checkers, or polka dots, enabling easy recognition by their flock of bombers to form up from various airbases over England as a leader to the formation of larger groups, which went onto the strategic bombing area... once the individual squadrons were joined up the Judas bombers returned to base, as they weren't fit for combat mission duty. During a large mission, it might take over an hour for the formation to form prior to the formation's actual departure to the target.
Perhaps my writing the explanation was clunky, so I'll add the following from http://www.mellophant.com/forums/showthread.php?9542-Judas-Goats
Which is where the Assembly Ships would come in.
These aircraft, usually having completed their schedule of active sorties, were painted in bright colors and patterns to be highly visible. The would begin orbiting around the airfield, and as they launched the sortie aircraft would form up on these Assembly Ships. Then, when the formation was complete, the lead ships of the strike would move to take the lead of the sortie, and the Assembly Ships, their jobs done, would return to base - since the very visibility that made them so useful for their role would have been a huge disadvantage in any kind of combat situation.
The bomber crews had more than merely mixed feelings about these ships, which would set up the strikes, send them off into harm's way, and then go back to the field themselves. Many of these crews came from farmer stock themselves and soon gave these Assembly Ships another name: Judas Goats.
Above 4 from http://www.mission4today.com/index.php?name=ForumsPro&file=viewtopic&t=5093&start=0&finish=15&printertopic=1
Above, the Ready and Willing. She was the assembly ship for the 466th Bomb Group. She flew 45 missions with the 93rd Bomb Group. https://www.pinterest.com/pin/321585229616141036/
B-24D Liberator ‘Pete the POM Inspector’ originally flew the 1 Aug 43 Ploesti mission with the 44th BG / 506th BS 'Heaven can Wait' (V), but aborted before the target and landed on Cyprus. Transferred to the 389th BG / 566th BS (EE W) at the beginning of Nov 43, and flew on combat operations through 26 Mar 44, then transferred to the 467th BG and became an assembly aircraft.
Lead Assembly Ship of 467th Bomber Group, US 790th Bomber Squadron, RAF Rackheath,
Above from http://ww2db.com/photo.php?source=all&color=all&list=search&foreigntype=A&foreigntype_id=32
and from https://www.facebook.com/photo.php?fbid=10204565400788074&set=p.10204565400788074&type=1
Update April 22nd 2015: http://www.warhistoryonline.com/war-articles/formation-ships.html
Handwritten caption from Bivens: 'My friend remembers it being named "Bucksheesh Benny" that it was used to fly Jack Benny around USA shows. Says it flew in North Africa with Benny and was eventually assigned to 389th as a hack and later as a form-up ship.