In the skies over Las Vegas, a high-stakes game is unfolding but the players are fighter pilots instead of gamblers and nothing is left to chance.

Just a short drive north from the flashy casinos and Elvis impersonators of Vegas, the US military stages elaborate mock air battles in the Nevada desert, where US airmen play the role of "aggressors," forcing less experienced pilots to hone their combat skills.

At the US Air Force's "red flag" exercises, fictional "aggressor" units fly F-15 and F-16 fighter jets painted in Russian-style camouflage, and the pilots employ tactics used by potential adversaries in Iran, China and elsewhere.

Serving in the aggressor units is a full-time job, a coveted assignment for specialists who try to prepare fellow airmen for the stress and intensity of aerial combat.

The aggressors are "a hand-selected crew," said Brigadier General Terence O'Shaughnessy, who led the 57th Adversary Tactics Group at Nellis Air Force Base, outside Las Vegas.

"We're able to pick our top pilots, our top cyber warriors and our top space warriors to come in and to be the experts. It's typically a three-year assignment," said the general, now deputy director for politico-military affairs in Asia on the joint staff.

In the first few days of a red flag exercise, young pilots are often stunned by the scale and speed of the war games, with their seasoned adversaries running circles around them.

"It's a very, very steep learning curve," O'Shaughnessy said.

The aggressors hack into their rival's computer networks, sift through dumpsters for mission documents and even extract information from unsuspecting pilots who sometimes spill secrets at Las Vegas bars.

The enemy force used to be comprised only of fighter jocks, flying warplanes for the "red team" in dog-fights against a "blue" force.

But since 2005, specialists in air defense, satellite and cyber warfare now take part, underscoring growing concern at the Pentagon over fresh threats to America's air power.

The Air Force prides itself on the realism of the war games but commanders worry the simulated missile, satellite and radar threats at red flag are outdated, resembling what allied aircraft faced during the 1991 Gulf War.

The war games include disrupting the satellite-linked global positioning system (GPS) for the "good guy" blue team, but the jamming is conducted on a small-scale because civil aviation authorities are concerned about endangering commercial airliners flying nearby, officers said.

Colonel Chip Thompson, the head of the Nevada training range, said there are plans to bolster the mock missile threat to reflect more advanced weaponry now on the market, including air defense systems that US officials fear Russia might sell to Iran.

In one scenario last week, the red side tried to lure their opponents into an area infested with simulated surface-to-air missiles (SAMs), a "SAM-bush."

The blue team saw through the ploy but decided to keep trailing the planes with the aim of taking out the sites, said Major Mike Culhane, one of more than 1,600 airmen taking part in this month's exercise.

The maneuvering was part of a war game in which the blue side had to rescue two F-15 pilots whose plane, according to the scenario, had been shot down in "bad guy land."

The plan called for clearing out enemy missiles from a 10-mile radius around the downed pilots, to ensure safe passage for the rescue helicopter.

The blue side more than once believed it had carved out a safe zone around the pilots, only to have one of its fighters "lit up" by yet another SAM site, said Culhane, an F-15 pilot at his first red flag.

"They just kept coming back up," he said. "When you're lit up, it feels real in the cockpit. It's not like a (flight) simulator."

After more than 90 minutes, the helicopter rescued the pilots, though one of them needed real-world medical attention due to dehydration.

The aggressors sometimes display a mischievous flair.

At this month's exercise, Colombian pilots -- taking part in the red flag drill for the first time -- were startled during a night flight when a Britney Spears song suddenly blasted out of their cockpit radio.

"It was a surprise for them," said Brigadier General Carlos Bueno, whose Colombian airmen realized the pop music was the work of the "enemy."

"They expected to hear static from jamming, but not that," he said.