As the U.S.-led airstrikes in Iraq and Syria against ISIS continue, it remains unclear exactly how the complex mission against the Islamic State group will unfold. But what is evident already as strikes escalate is that U.S. defense companies are already cashing in.

Just days after the strikes in Syria began on Sept. 23, shares of Lockheed Martin, Northrop Grumman, Raytheon and General Dynamics all reached record prices.

"President [Barack] Obama has predicted that this air campaign could last for a long time, so that signals billions of dollars in additional sales of munitions, of spare parts and potentially also of aircraft," said defense consultant Loren Thompson.

But more than an increase in stock prices, the widening conflict, which started in Iraq in August before moving to Syria just one week ago, not only brings new orders to the defense industry, it can also help pay for new technology and even help stave off the closure of production lines and keep military hardware from being cut.