HERO AT LARGE -- AMC Academy, Arlington, Avalon, Beacon Mall, Dale Cinema, Fair City Mall, Landover Mall, Laurel Town Center, Mercado, Roth's Montgomery, Roth's Tysons Corner and White Flint.

The hero of "Hero At Large" is not exactly Superman. He's more the type for whom the Pajama Corporation of America (signing itself "A Concerned Member of the Community") has to insert a warning into each package of Superman pajamas that "people cannot fly."

No, but people can still look up to heroes, and people can still aspire to heroism. That simple but appealing point is the theme of this film, which is as dear and funny as -- well, as a kid in Superman pajamas solemnly declaring for truth, justice and the American way. Without the fancy effects of the high-budget super-hero film, this one achieves the same gentle comedy through its deliberately naive enthusiasm.

It takes some sophistication to get that combination right. If the point of view too unreservedly admires the comic strip mentality, it will itself seem primitive; if it's too sociologically analytic, it will kill the charm. There has to be a slight distance which says "This is silly, but wonderful," without seeming to patronize.

The chief source of this success in "Hero At Large" is John Ritter, who plays the hero with equal parts of warmth and humor. These characteristics are well written into A.J. Carothers' story of an unsuccessful actor who, wearing a super-hero costume for a promotional job, happens to foil a real crime and then is drawn into the idea of playing city savior. And the charm of the hero role is deftly complemented by the modern toughness of Anne Archer, as his girl friend, Kevin McCarthy, as a politician and Bert Convy as a public relations expert.

But it is the hero who must make it fly. And Ritter does his job of being an average non-success with such cheerfulness that he makes it all as touching as it is comic.