Fans of the early '80s ABC television series The Greatest American Hero know the character of Ralph Hinkley owes a pretty big debt to Superman. Warner Bros. thought so, too, and even went so far as to sue ABC over what they interpreted as copyright infringement. The case was ultimately dismissed. But while Hinkley shares some qualities with Superman, he does with other heroes, too.
In fact, Hinkley's powers and origin (played by William Katt) shares the DNA of a number of other prominent superhero characters from the era. Some of them are easy to pick out, while others take a little bit of detective work.
Ant-Man
Ralph Hinkley and Scott Lang, Ant-Man, have a lot in common. They're both regular guys just trying to make it in the world. They both receive special power suits, and they both shrink down to a miniature size. Shrinking is just one of the many abilities that Hinkley (who never adopted a formal superhero name) gains from the alien suit he's given. In the second season, he's given a second instruction manual by the aliens, having lost the first, but loses it again when he shrinks down to a minuscule size.
Iron Man
Similar to Ant-Man, Iron Man uses a specialized suit to fight crime. Though the alien suit Ralph Hinkley wears and the suit of armor Iron Man do differ in form, the idea is basically the same. They're also both government liaisons, as Tony Stark was early in his career. Hinkley works with FBI Special Agent Bill Maxwell (played by Robert Culp) and attorney Pam Davidson (Connie Sellecca) to fight crime and eventually fight against the Soviet Union to prevent World War III.
Guardian
A fair number of superhero characters in comic books wear suits that give them their powers. One of them is Guardian, from the Canadian superhero team Alpha Flight. James MacDonald Hudson is a scientist, whose suit of battle-armor, gives him the dual abilities to fly and manipulate Earth's magnetic field. Guardian was originally Weapon Alpha, and then Vindicator. He first appeared in The X-Men #109 in February 1978, just a few years before the debut of the television series.
Green Lantern
The Greatest American Hero doesn't have any direct connection to Green Lantern, but elements of his powers and origin are reflected in Ralph Hinkley's. Like Hal Jordan, Ralph receives his powers via an alien object, in this case, the red and black suit. Both the suit and Power Ring grant their respective owners enormous powers.
Hal Jordan doesn't immediately understand the Power Ring and it takes some trial and error, as it does with Ralph, to learn how to use it. Jordan ultimately does, with his mythology expanding out dramatically with the introduction of the Green Lantern Corps, the subject of a forthcoming HBO Max series and a great animated series from the 2010s.
Invisible Woman
The alien suit that Ralph Hinkley wears is sort of a magic hat. He can pull anything out of it. In the fourth episode of the first season, he develops the ability to turn invisible. Invisibility is a superpower fairly common in comic books but best associated with the Invisible Woman from the Fantastic Four. Sue Storm has continued to develop and refine her power - including creating invisible shields - since her debut in the early 1960s at the very beginning of the Marvel Universe.
Spider-Man
Ralph Hinkley doesn't shoot any webs or crawl on any walls, but his fumbling discovery of his powers recalls a lot of early Peter Parker. Learning his powers is a full-time job for Hinkley, played by William Katt, the son of Barbara Hale who played Della Street on the original Perry Mason.
One of the funniest aspects of the series is that he can fly but never learns to land. Every time he does, he crashes or stumbles on the ground or into a wall, since he lost the instruction manual for the suit. Some of Tobey Macguire's best moments as Spider-Man are of him learning his new powers.
Jean Grey
Jean Grey is one of the most powerful X-Men in the comic books, and one of the most powerful mutants ever. She is an Omega-Level telepath and telekinetic and if Ralph Hinkley were graded on that same scale, he likely would be, too. He displays both psychic abilities over the course of the show. He can read the minds of others (and telepathically communicate with animals). He's also able to use telekinesis to levitate objects and slow them down, as he did with a runaway freight train.
Captain Mar-Vell
Captain Marvel is one of Marvel's greatest and most iconic superheroes. Carol Danvers didn't start off in the role, though. One of the things the 2019 Captain Marvel got right was continuing the thread, in an updated way, of Mar-Vell being responsible for Carol receiving her powers. One of those powers is precognition, which Ralph Hinkley also has.
During the television series, Ralph was able to see into the future, and when he did have a vision, people in that future were actually able to see him as well.
Shazam
Shazam and Superman share a lot of surface-level similarities, which led to some litigation back in the Golden Age of comics. The strength, speed, and overall look of Shazam, originally called Captain Marvel, inform on some level that of Ralph Hinkley. Though the process for how they arrive at their powers is different, the basic method is the same. Both Ralph and Billy Batson inherit their powers from cosmically powerful beings and then have to struggle to learn how to use them, as Batson hilariously did in the Shazam! movie, one of the best superhero films from 2019.
Superman
Superman is the biggest and most obvious influence on The Greatest American Hero. It was never really in doubt. The pilot episode features a clip of the Man of Steel from the 70s animated series Super Friends playing in the background. The show also makes numerous other nods to the concept of Superman, including Ralph refusing to enter a phone booth to change into his alien suit. Though the show was litigated just as the original Captain Marvel at Fawcett Comics was, everything worked out in the end.