The Wikimedia Commons website, PixaBay.com and Flickr.com provide free pictures of airplanes. While Wikimedia Commons has a specific category for aircraft, users must search for airplane pictures at Flickr.com and PixaBay.com through the search box.
As of 2015, the Wikimedia Commons aircraft category contains 32 subcategories for pictures of airplanes, including registration, country and manufacturer. The pictures at Wikimedia are protected by a Creative Commons copyright license, so users may copy and modify the pictures for free as long as they cite their authorship and distribute them under the same Creative Commons copyright license.
PixaBay.com provides free photos of airplanes under a public domain license, which means that users can freely use, distribute, modify and copy the pictures. As of 2015, PixaBay.com features over 1,300 pictures of airplanes. Pictures are not organized by categories, so users must search for airplane pictures using the search box.
As of 2015, Flickr.com features over 2 million pictures of airplanes under different copyright licenses. Unlike Wikimedia Commons, Flickr.com does not categorize airplane pictures, so users must use the search box instead. Users may also narrow the search by colors and copyright license, as well as by orientation and size, using the advanced search menu.