There's no Republican candidate yet in the 2012 race for Missouri governor.
But the GOP committee is already running a radio spot that lambasts the Democratic governor's air travel expenses, referring to him as "Air Jay".
Nixon has come under fire for billing state agencies $400,000 over two years for his air travel around the state.
State auditor Tom Schwiech, a Republican, has said he will review Nixon's travel practices as part of a scheduled audit.
In a statement Nixon's campaign spokesman Jack Cardetti said it's puzzling that the GOP would criticize the governor for traveling the state to listen to his constituents.