Chaff
The objects falling out of the plane is chaff or window, which is long streds of aluminum. Welsh physicist, Joan Curran invented chaff during her time at the Telecommunications Research Establishment. The thin metal strips reflect the radio waves, and with the right conditions the reflected waves gives the impression that there is a large object on radar detectors. Thus, the Allies (mainly Great Britain, France, and the United States) had a way to distract the Axis (mainly Germany, Italy, and Japan) in battle. After multiple tests in 1943 the chaff was used on the battle field during Operation Gomorrah in Hamburg, Germany. Chaff's largest use was on June 5, 1944, the day before D-Day. The run included two chaff drops and dummy parachutists.
To learn more about chaff go to: https://www.smithsonianmag.com/innovation/woman-whose-invention-helped-w...
http://www.nationalarchives.gov.uk/education/worldwar2/theatres-of-war/w...
F/O L. Howard, No. 1 RAFFPU. [the Lancaster releases bundles of 'Window' over the target during a special daylight raid on Duisburg]. 1944. Photograph. Wikimedia Commons. https://commons.wikimedia.org/wiki/File:Lancaster_I_NG128_Dropping_Load_... (Accessed January 3, 2019).
Public Domain
Public Domain is a copyright term that is often used when talking about copyright for creative works. Under U.S. copyright law, individual items that are in the public domain are items that are no longer protected by copyright law. This means that you do not need to request permission to re-use, re-publish or even change a copy of the item. Items enter the public domain under U.S. copyright law for a number of reasons: the original copyright may have expired; the item was created by the U.S. Federal Government or other governmental entity that views the things it creates as in the public domain; the work was never protected by copyright for some other reason related to how it was produced (for example, it was a speech that wasn't written down or recorded); or the work doesn't have enough originality to make it eligible for copyright protection.