Most collectors today wouldn’t consider aviation a sport. But in the pre-war era, these cards were almost always considered to be sport issues.
Similar to auto racing, aviation did not start to gain popularity, really, until the early 1900s. But the sport found its way into several multi-sport sets and was even featured in some aviation-exclusive releases.
Below are known sets featuring only aviation or those where aviation is a significant part of the series. Note that, this page has a focus on the aviators, not necessarily just the planes themselves. So sets like the 1940 Wings Cigarettes set, which merely is a set of airplane cards, are not included here.