Sen. Claire McCaskill, D-Mo., has sold a private plane she co-owns with her husband, months after her use of it for official business and failure to pay back taxes created a political headache... First she repaid the government $88,000 after she was criticized for reimbursing herself for use of the plane on official and political travel. Then she paid $287,000 in back taxes, penalties and interest to St. Louis County. ... McCaskill, seeking re-election in 2012, faces a tough race in a state she narrowly won in 2006. Republicans have pounded McCaskill on the plane, dubbing it "Air Claire" .