Militants from the Islamic State overran a key government military base in Raqqa, Syria on Sunday, taking control of an airfield and possibly missiles and fighter jets, though it's unlikely those jets can fly.

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Last week, the group published a video, showing the beheading of the American journalist James Foley, and, in taking large swaths of territory in Syria and Iraq, the militants have shown brutal ambition, slaying both security forces and civilians in their path.

Given the group's ruthlessness, even the prospect that militants were aiming to get airpower caused concern among long-time observers of the region.

“You could, in theory, take one of those [jets] and slam it into an embassy or a prime minister’s office," Anthony Cordesman, a Middle East security expert at the Center for Strategic and International Studies, told Mashable. "There’s not really much anybody could do about it."

But it's unlikely the extremists captured any working fighter jets and, if they did, it's unclear whether they have pilots to fly them. It's possible that some airmen have defected to the Islamic State from the Syrian or Iraqi militaries, but experts told Mashable they have no proof.

Even if an extremist was able to fly a captured Syrian jet, experts agree that the Islamic State has no way to maintain large military vehicles. As soon as a plane had problems, it would have to be grounded for good.

Instead of worrying about Islamic State jets, experts including Cordesman say that their opponents should be concerned by the smaller arms and vehicles that Islamic State fighters likely took from the Syrian government outpost.

In this photo taken on June 23, Islamic State fighters parade in a commandeered Iraqi security forces armored vehicle down a main road in Mosul, Iraq.

“They probably took a bunch of the normal stuff," said Jeffrey White, a Middle East security expert at the Washington Institute. Among "normal stuff," White cited tanks, anti-aircraft guns, artillery and ammunition." “They don’t have any capacity to establish any kind of an air force yet, though they’re captured some airfields.”

Islamic State militants have continued to ransack weapons depots across Syria and Iraq, amassing a terrifying arsenal, and getting their hands on U.S.-made Humvees which gave their forces more mobility and firing power from mounted turrets.

The radicals have also captured anti-aircraft guns with which they fire at their enemies on the ground, effectively using those weapons as high-caliber machine guns, and they've stockpiled artillery units used to bombard any enemies within sight.

The fighters have grabbed machine guns, pistols and ammunition left behind by the U.S., according to Dakota Wood, a foreign policy expert at the Heritage Foundation, a conservative think tank.

“When relatively unorganized units are fighting each other, anything that sprays bullets can have some level of effect," Wood said.

While U.S.-made weapons and equipment form part of their arsenal, the fighters have captured more Russian-made assault rifles and corresponding ammunition, which are simpler to use.

“It's one thing to have to operate a vehicle at long ranges and against a sophisticated opponent," Cordesman said. "But if you’re simply shooting people with direct fire, it doesn’t require a hell of a lot of training.”