Pentagon leaders and thousands of military contractors across the country might be wondering just what President-elect Donald Trump has in store for them.

In two tweets this month that sent shockwaves through defense companies and their lobbying firms, Trump criticized the spiraling costs of building a new Air Force One and a fleet of F-35 fighter jets.

That criticism triggered meetings a week ago with the heads of those two projects’ main manufacturers, Boeing Co. and Lockheed Martin Corp., at the billionaire’s Mar-A-Lago resort in Palm Beach, Fla. Trump said afterward that he’d extracted promises to cut costs.

But it remains to be seen whether Trump will be able to stay on top of Pentagon excess after he becomes president Jan. 20. The day after Trump met with the leaders of the two defense contractors, the Pentagon announced a long list of spending projects that totaled nearly $550 million.

Trump will have a difficult time focusing on that wide range of spending and carrying out his pledge to pay for expanded military operations by trimming Pentagon waste, say experts on the way the Pentagon oversees its contracts. He won’t find many friends in the process, they note.

“He’s going to encounter a Pentagon bureaucracy that will instinctively say ‘no’ to most reforms he proposes,” said Todd Harrison, a former defense lobbyist and retired Air Force Reserves captain who’s now an analyst with the Center for Strategic and International Studies in Washington. “He’s certainly not the first president to come in saying we can cut waste and abuse within the Pentagon budget. Very few have had much success.”

William Hartung, who in 2011 wrote a book about the clout F-35 contractor Lockheed-Martin wields in the U.S. Congress, made a similar observation about the Pentagon.

“They don’t scrutinize the original bids carefully enough, so contractors come in with a low bid while understanding that they’re not going to meet it,” Hartung said. “And then the Pentagon will add requirements and new features along the way. Eventually the costs get out of control.”

By the time that’s evident, however, inertia keeps the program going. “Once they put a certain amount of money on the table, they’re reluctant to end or dramatically scale it back,” Hartung said.

Whether Trump will be able to change that culture is what experts in Pentagon procurement are watching. With a price tag of $400 billion and rising, the F-35 Joint Strike Fighter, for example, already is the most expensive weapons system ever built. It could end up exceeding $1 trillion by the time all planned 2,457 planes are manufactured.

The pre-inaugural meetings with the defense firm bosses give Harrison some grounds to hope. The meeting is in keeping with Trump’s penchant for the unconventional approach.

Afterward, Boeing CEO Dennis Muilenburg pledged to get Air Force One built for less than the $4 billion budgeted. Lockheed Martin’s CEO Marillyn Hewson was less committal, pledging only that her company is dedicated to “delivering an affordable aircraft to our U.S. military and our allies.”

“I think he will be less likely to listen to the bureaucracy,” Harrison said of Trump. “What we’ve seen so far is that he’s more self-confident and he’s willing to say things and do things that buck the establishment. He almost takes joy in it.”

Hartung, director of arms and security research at the Center for International Policy in Washington, said he, too, was impressed with Trump’s meetings with the CEOs. But the new president will face deep-rooted problems in targeting bloated Pentagon spending, he cautions.

“If he doesn’t change the budget and contracting procedures or inject some form of accountability, then it might just turn out to be good public relations as opposed to a real war on waste,” Hartung said.

The challenge of bringing Pentagon spending under control is evident almost daily in the military’s lists of the contracts it’s awarded. Some are for new projects, while others are for modifications — almost always price increases — of ongoing ones.

A look at the announcement from Dec. 23, the day after Trump’s meetings with Hewson and Muilenburg, suggests how daunting Trump’s challenge will be.

The announcement listed 12 projects for the Army, the Air Force and three other defense agencies, totaling $549.4 million.

The new spending extends as far ahead as 2022, well into Trump’s second term should he choose to run again and be re-elected.

While Trump has promoted the notion of pumping $1 trillion into upgrading the country’s roads, bridges and other infrastructure, the list shows how military spending is a permanent stimulus and jobs plan spread over every state and touching each of the 435 congressional districts.

On just that one day, the almost $550 million was spread among 22 states plus the District of Columbia.

Distribution was completely bipartisan. Significant shares went to defense contractors and military bases in blue states — California, New Jersey, Illinois, Massachusetts, Minnesota, Connecticut and Hawaii — red states — Texas, Missouri, Utah, Alabama, Arizona, Indiana, Alaska, Oklahoma and South Dakota — and swing states — Florida, Ohio, Virginia, Nevada and New Mexico.

While some congressional fiscal hawks have tried to rein it in, Pentagon spending has been hard to corral, especially since the Sept. 11, 2001, attacks.

The total this year is about $595 billion, almost 50 percent higher than 15 years ago even with inflation taken into account. Non-defense spending has increased by some 13.5 percent during the same period.

And that’s only the money that the Pentagon gets directly for troops, weapons, bases and support systems. The cost nearly doubles when you add to it other related expenditures such as $164 billion that the Veterans Affairs Administration receives; $100 billion the government pays in interest on past defense debt; $51 billion the United States gives in military aid to foreign countries and $20 billion for the Energy Department to maintain and upgrade U.S. nuclear arms.

And there have already been defense cuts since President Barack Obama ended major American military participation in the Iraq and Afghanistan wars.

Indeed, Obama is the rare president who actually has succeeded in ending a weapons program — the 2009 closeout of the F-22 Raptor tactical stealth fighter jet. But that victory came only with the assistance of heavyweight Republicans, then-Defense Secretary Robert Gates and Republican Sen. John McCain of Arizona, who called the plane a Cold War relic and said the 187 already in service were more than adequate.

Earlier Trump predecessors have met with mixed results in trying to scale back Pentagon megaprojects.

Republican Dwight Eisenhower fought hard in the late 1950s against development of the B-70 nuclear-armed strategic bomber. Arguing that land-based nuclear missiles already targeted the then-Soviet Union with greater power, the former World War II commander significantly scaled back its production.

Democrat Lyndon Johnson’s Pentagon chief, Robert McNamara, pushed deep spending cuts in the 1960s based on his business background as head of the Ford Motor Co. But they stalled as the defense budget exploded during the Vietnam War.

Under Republican Richard Nixon, a top Air Force civilian manager named Ernest Fitzgerald testified to Congress in the 1960s about a $2.3 billion cost overrun the service had tried to conceal in developing the C-5A transport plane, another Lockheed Martin project whose price tag had ballooned.

Then-Defense Secretary Melvin Laird fired Fitzgerald under orders from Nixon to “get rid of that son of a bitch,” according to a recorded White House conversation released during the Watergate probe.

On the Dec. 23 list of new contracts, the biggest prize, $313.9 million, was to maintain engines for the F-22 Raptor. It will be divided among Air Force bases in California, Texas and five other states.

For a separate project, one defense contractor in Orlando, Fla., Longbow Limited Liability Co., will get $25 million “to provide live-cycle contractor support for the fire-control radar and unmanned aerial system tactical common data link assembly.”

That’s an example of the highly technical language that is difficult for lawmakers to decipher, much less use to make informed spending decisions.

One contractor, Sikorsky Aircraft Corp. of Stratford, Connecticut, on the list will get $35.7 million to develop part of an automatic-piloting assembly called ALIAS, the kind of snazzy-sounding acronym Pentagon planners love. It stands for “Aircrew Labor In-Cockpit Automation System.”

In announcing the project, the Pentagon explained: “The goal of the ALIAS program is to create an easily installable/removable kit that is extensible across 80 percent of Department of Defense aircraft and some commercial aircraft, which automates co-piloting functions to enable reduced crew operations.”

Sikorsky is an affiliate of Lockheed Martin, the same company Trump went after for its soaring F-35 costs.