Although the 747-200 was developed after the 747-100, it was built during roughly the same time frame. The first -200 went into commercial service in 1971, and Boeing delivered a total of 393, the last in 1991. Although its external appearance is nearly identical to the 747-100, it was designed to carry more payload. In addition to being offered as a passenger airplane, the -200 was the first 747 to be configured as a freighter, a combination passenger-freighter and a convertible.The 747 Freighter has a hinged nose to allow cargo loading through front of the airplane, with the option of a large side-cargo door. The 747-200 Convertible was configured to serve as a passenger airplane, a freighter or a combination of both. This airplane responded to airlines' needs to carry different payloads at different times of the years, such as higher passenger capacities during the summer and more cargo during the winter. In 1990, two 747-200Bs were modified to serve as Air Force One and replaced the VC-137s (707s) that served as the presidential airplane for nearly 30 years.