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If you’re honest, you’ll probably admit that the first time you heard of “Cowboys & Aliens,” it made you think of “Snakes on a Plane”—a title so absurdly on-the-nose that it was at once ludicrous and irresistible. But of course “Snakes” turned out to be all sizzle and no steak. While this movie is no filet mignon, it’s the cinematic equivalent of a big, juicy if not terribly nutritious hamburger—a rousing action-adventure that might not have a brain in its head but offers plenty of visceral excitement, seasoned with a hip, though not spoofing, attitude. In other words, a cool new “War of the Worlds” set in the Old West.

Westerns and sci-fi have, of course, been bedfellows before. When Gene Roddenberry pitched “Star Trek” to NBC, he supposedly described it as “Wagon Train” in outer space, and “Star Wars” certainly owes a lot to the oater cliffhangers of George Lucas’ youth. But “C&A” actually combines the two genres in a tale that situates an alien invasion of earth on the nineteenth-century American frontier. And it does so without disdaining either genre. There’s wry humor sprinkled throughout the picture—not least in Harrison Ford’s crinkle-eyed performance. But “Cowboys & Aliens” basically presents its story in a straightforward, serious way. This is not the Mel Brooks send-up the title might lead you to expect.

The screenplay, cobbled together by seven writers from Scott Michael Rosenberg’s graphic novel, begins with mysterious, inexpressive hero Jake Lonergan (Daniel Craig) awakening in the desert without a memory but with a futuristic bracelet strapped to his wrist. After blithely disposing of three ruffians who attempt to take him prisoner, he rides into the near-abandoned mining town of Atonement, where he quickly falls afoul of Sheriff John Taggart (Keith Carradine), who recognizes him as a wanted man, and of local potentate Woodrow Dolarhyde (Ford), the inevitably tyrannical cattle baron, whose smarmy son Percy (Paul Dano) he’s calmly dressed down (and whose gold he’s stolen).

But before the usual western dust-up can begin, Atonement is attacked by a swarm of swift airships—hardly a common sight in late nineteenth-century New Mexico—that blast the town apart and carry off some of the townspeople—including Percy and Sheriff Taggart—on metal ropes. Naturally the survivors form a posse to chase down the beastly pilot of the one craft that’s been shot down by Lonergan’s wristband, which proves a pretty remarkable weapon. The group includes all the usual suspects—Dolarhyde and his Indian scout Nat Colorado (Adam Beach), world-wise town preacher Meacham (Clancy Brown), meek barkeep Doc (Sam Rockwell)—whose wife is among the abductees—and young Emmett (Noah Ringer), Taggart’s grandson. They’ll eventually be joined by members of Lonergan’s outlaw gang and braves from an Indian tribe that has also been attacked by the aliens. And there’s one outsider—beautiful but enigmatic Ella Swanson (Olivia Wilde), who prods Jake to recover his memory—which he does haltingly, via some hazy flashbacks that fill in the backstory.

In making its way to the exciting—if not always ideally choreographed and edited—showdown between monsters and frontiersmen, “Cowboys & Aliens,” directed with poise by Jon Favreau, blends western and sci-fi elements with surprising success. At one moment it will conjure up recollections of “The Big Country” or “The Searchers,” and elsewhere call to mind “Alien” and “Invaders from Mars.” It generously applies western tropes—the grudging growth of respect between Dolarhyde and the Indian chief, the cattleman’s increasing respect for his longtime scout, a “boy and his dog” subplot, the barkeep’s instruction in how to use a gun—while going for some pretty horrific scenes of humans tortured by the creatures. Sometimes it simply mingles the two elements. When Nat lassos an alien or Jake rides one of the spaceships as though it were a bucking bronco, for instance, there’s a giddy amalgamation. And while the picture certainly plays some of the oater conventions for smiles—Walton Goggins’ sniveling outlaw springs to mind—it also has its share of genuinely emotional moments, including a couple of dramatic death scenes. You might not expect this blend of familiar elements from very different cinematic worlds—or the tonal twists—to work, but amazingly they do.

From the technical perspective “Cowboys & Aliens” is impeccably made; one would expect no less from a movie with Ron Howard and Steven Spielberg among the small army of producers. Matthew Libatique’s widescreen cinematography (thankfully without 3D “enhancement”) is equally successful in the bright outdoor scenes and the darker horror-movie ones, and the production design (Scott Chambliss), art direction (supervised by Chris Burian-Mohr), set decoration (Karen Manthey), costuming (Mary Zophres) and effects (by a raft of companies, including Industrial Light & Magic) could hardly be improved on. Dan Lebental and Jim May’s editing keep things crisp, except for some muddiness in the final battle scenes, and Harry Gregson-Williams’ score nicely blends western motifs with more contemporary action-adventure beats.

And the actors throw themselves into the spirit of things with gusto. Craig manages the stone-faced gunslinger business far better than Scott Glenn did in “Silverado,” and Ford brings his now-grizzled shtick, as well as a touch of real nastiness, to the stock figure of the cattleman. The supporting cast hasn’t a weak link, but Dano and Beach stand out as Dolarhyde’s high-strung real son and his unappreciated “adoptive” one.

With so many big summer movies going the mere cookie-cutter route, it’s refreshing to encounter one that, even if it basically follows well-worn formula, dresses it up in nifty new duds.