Work cat.: Flash Gordon (Motion picture : 1936). Rocket ship, 1980.

Last starfighter (Motion picture). The last starfighter, 2009.

López, D. Films by genre, ©1993: p. 274 (subgenre listed under Science Fiction Film: Space Operas. Applied to space adventure stories with spaceships on some rescue mission or with intergalactic starships battling enemy forces, bug-eyed monsters and the like. A famous recent example is Star Wars (1977). Examples listed include: Flash Gordon (1936); Buck Rogers (1939); Barbarella (1967); Star Trek (1979); Star Trek II: The Wrath of Khan (1982); Space Raiders (1983); The Last Starfighter (1984); separate subgenre also listed: Space Travel Films (Space Exploration Films, Space Films, Space Flight Films). "Space operas fit into a different class of space flight films.")

Wikipedia, Jan. 22, 2019 (Category: Space opera films; films belonging to the space opera subgenre of science fiction; category has the following 2 subcategories: American space opera films; Space adventure films‎)

Evans, J. Top 5 space opera films, via ScienceFiction.com website, posted July 28, 2011, viewed on Jan. 22, 2019 ("Space opera" is a phrase that defines a genre of science fiction literature, and can also be applied as a category for movies. Typically, space opera occurs on a galactic scale, involves intelligent races other than humans, and has multiple types of spacecraft, from speedy corvettes to battleships capable of destroying planets. There is plenty of action and adventure in space opera. One thing you can be nearly certain of when watching a space opera film is that you won't get bored)

Wright, G. The science fiction image : the illustrated encyclopedia of science fiction in film, television, radio and the theater, ©1983, via Google books, viewed Jan. 22, 2019: p. 282 (space opera films)

Erickson, M. Science, culture and society, 2016: p. 185 (Star Trek II: The Wrath of Khan (Nicholas Meyer, 1982); the film is a good example of the subgenre of space opera, where heroic spaceship captains save the world after monumental and visually exciting space battles) p. 190 (three key features that a space opera must have: a spaceship, an exciting adventure story and a tendency towards a formulaic plot or mediocrity)

Large-scale action and adventure films involving space travel.