At first, Ryan Costello didn't know what to think of the low-flying propeller plane and its admonishing message. Shortly after the Gettysburg College Bullets hit the field at Saturday's homecoming football game against Ursinus College, a plane circled over the field for more than an hour with a sign trailing behind it for thousands to see.It read: "GC: Teach the Truth...Go Bears!"The psychological tactic was the most recent barb in a campaign by the Sons of Confederate Veterans, whose 34,000 members are still bristling over a September art exhibit hosted by the college that featured a Confederate battle flag hung...