The U.S Defense Department is getting a helicopter upgrade. Its signed up for a fleet of new options for Marine One, the designation for whichever Naval chopper carries the president, in a $1.24 billion initial contract with Sikorsky Aircraft Co. Sikorsky, a Connecticut-based company that has government contracts around the world (including with at least 10 other heads of state), has flown every American president since Dwight D. Eisenhower first climbed aboard in 1957. The new helicopters will replace the current fleet, which includes models developed as early as 1974 — the Defense Department has been trying to upgrade for more than a decade.