To promote the -200 version of the 747, which featured ten upper deck windows instead of the three windows standard on the -100 version, Boeing painted extra windows on a 747-100 to use for marketing purposes for the new airplane. The 747-100 and -200 aircraft, including passenger, freighter, and combination models, were produced simultaneously for many years. Although external dimensions of the two series were the same, there were differences including gross weight, engines, and a substantial change package.