BOSTON, March 7 (Reuters) - Delta Air Lines (DAL), the No. 3 U.S. carrier, said on Thursday that it plans to proceed with its previously announced $400 million redevelopment of a terminal at Boston's Logan International Airport. Delta announced the plan to upgrade and expand Terminal A at Logan in 1999 and expects the work to be completed in 2005. The airline will consolidate all of its operations at Logan in the terminal, which will serve only Delta passengers. The airline said its Delta Shuttle operations will relocate from Terminal A to Terminal B starting on April 7 for the work.