Defense Secretary Jim Mattis said Monday night that the military would have enough money to buy 120 F/A-18 Super Hornets or 300 more AH-64 Apache helicopters if Congress allowed it to close unneeded bases.

Mattis used his first testimony on the 2018 defense budget request to press the House Armed Services Committee for another round of base closures around the country, a longtime goal of the Pentagon that has been repeatedly blocked by lawmakers.

This time, Mattis pitched the potential savings but also brought along concrete examples for a committee with many Republicans hoping to increase purchases of new aircraft, ships and other major weapons systems.

"We forecast that a properly focused base closure effort will generate $2 billion or more annually — enough to buy 300 Apache attack helicopters, 120 F/A-18E/F Super Hornets, or four Virginia-class submarines," Mattis said. The aircraft are made by Boeing and the subs are made by General Dynamics Electric Boat and Newport News Shipbuilding.

As part of President Trump's defense budget, the Pentagon has proposed a round of base closures in 2021. The last round of so-called BRAC occurred in 2005.

Overall, the 2005 closures and earlier BRAC rounds save the military about $12 billion per year, according to the Pentagon.

However, the closures are unpopular among many lawmakers because they remove military facilities that can bring local jobs and money, and they require a big investment of federal money upfront before paying off in future years.