Superman vs. Batman didn't fly. A hyped Aquaman TV show went belly-up without ever airing and the movie is an Entourage joke. A Wonder Woman movie is struggling to get off the drawing board.

The heroes may be down, but they're definitely not out.

In news guaranteed to give fanboys conniptions, Warner Bros. is developing an ambitious feature film based on DC Comics' Justice League of America that will gather together some of the biggest superheroes, according to Daily Variety.

"The Justice League of America has been a perennial favorite for generations of fans, and we believe their appeal to film audiences will be as strong and diverse as the characters themselves," the studio's president of production, Jeff Robinov, told the trade.

Conceived by DC in 1960, the JLA originally had seven members: Superman, Batman, Wonder Woman, Aquaman, the Flash, Green Lantern and Martian Manhunter, the green-skinned detective who was left out of the '70s Saturday-morning cartoon classic Super Friends, but has made a comeback in the Cartoon Network's new Justice League Unlimited series.

The JLA had several other members come and go over the years, including Hawkman, Green Arrow, Plastic Man, Aztek, Atom and Captain Marvel. Together, they battled various supervillains, including Lex Luthor, Braniac, the Joker, Black Manta and Gorilla Grodd.

Warners has reportedly tapped the writing team of Kiernan Mulroney (brother of actor Dermot) and wife Michele to tackle the screenplay. The big question facing studio suits now is casting, both in terms of heroes and actors.

The studio once planned to combine its two long-dormant franchises in a Superman vs. Batman movie that was ultimately scuttled when would-be director Wolfgang Petersen opted to make Troy.  Instead, Warners managed to revive both properties via Christopher Nolan's Batman Begins, starring Christian Bale as the Caped Crusader, and Bryan Singer's Superman Returns, with Brandon Routh as the Man of Steel.

Superman and Batman are DC's two most popular characters and key members of the Justice League so they would seem to be sure bets for any JLA film. But Bale is committed to starring in the Dark Knight sequel due next year and Routh is on board for another Superman due in 2009. Warners would risk diluting the heroes' respective staying power by using different actors.

Warners has also been trying to launch a Wonder Woman franchise, but writer-director Joss Whedon (Buffy the Vampire Slayer) recently dropped out of the project over concerns about his script and casting choices and that project is now stalled.

Meanwhile, the studio has tapped Night at the Museum director Shawn Levy to shepherd a Flash movie. Like Wonder Woman, the speedster was previously the subject of a TV show but a film version has never gotten out of development.

Aquaman is also waiting for his closeup. The pilot for a planned spinoff of Smallville was rejected last year by the CW and the closest the dolphin hugger has come to the big screen was on HBO's Entourage.

Based on that kind of track record, getting JLA off the ground will probably take a superheroic effort.