Senator Bob Corker, who represents FedEx Corp.’s home state of Tennessee, is blocking aviation- funding legislation over the prospect that language may be added later helping unions organize at the company, according to Business Week. Corker’s action extends a years-long fight in Washington between the mostly non-union FedEx and its unionized rival United Parcel Service Inc. over how workers at both companies should be treated under U.S. labor laws. The dispute is over a measure reauthorizing funds for the Federal Aviation Administration.