Douglas Aircraft opened its first World War II aircraft plant at Long Beach Airport in 1941, and built nearly 10,000 aircraft here over the course of the war. Under McDonnell Douglas and Boeing (which took over McDonnell Douglas in 1997), the airport continued to produce military and civilian aircraft until 2015, when the last C-17 transport aircraft left the big hangar at the southern end of the field. At the northern end of the airfield were more production and R&D complexes, some of which were used for both early and recent space programs. Boeing still maintains some of these operations today, at its Douglas Center, though much of the sprawling complex has been redeveloped into an office park and retail, and the remaining big hangar at the north end of the airport is leased to Mercedes-Benz as a logistics facility. The C-17 plant, at the southern end of the airport, is now used by Relativity Space, a company formed in 2015 to develop commercial rockets.