After more than half a century of production, the final Boeing 747 plane rolled off an assembly line in Washington state on Tuesday evening. The machine will head to Atlas Air to become a cargo plane, as the company retires the model that was known as the Queen of the Skies. The 747 models, distinctive for their massive size and prominent second floor, became Boeing's most popular plane. Its size allowed it to be part of many iconic and revolutionary space-related projects over the years, including ferrying the Space Shuttle from a landing strip in California to a launch site across the country in Florida.