The behind-the-scenes lobbying dogfight between American aerospace titans Boeing and Lockheed Martin reached new heights in recent weeks as both defense firms angled for tens of billions of dollars in fighter jet deals from the Trump administration. Now Chicago-based Boeing, which in recent years had backed off its efforts to keep Joint Strike Fighters off the decks of Navy aircraft carriers, is circulating a one-page white paper making a case for fewer F-35s and more F/A-18s.

“The U.S. Navy currently plans to have a Carrier Air Wing mix of 3 squadrons of F/A-18 Super Hornets and 1 squadron of F-35Cs in 2028 transitioning to 2 squadrons of F/A-18 Super Hornets and 2 squadrons of F-35C in 2033,” the white paper reads. “This leaves significant capability gaps against emerging threats and under the current aircraft procurement plan leaves the Navy with a significant inventory shortfall.”

The paper — which is unbranded and does not mention Boeing — argues that “Adding additional F-35Cs will not solve this capability gap and will be prohibitively expensive. Adding Advanced Super Hornet F/A-18XT squadrons gives the Carrier Air Wing a significant edge against future adversaries and is an affordable solution to the inventory challenge.”

Boeing argues its carrier air wing would save the Pentagon $8 billion in aircraft purchases alone, then an annual $1.4 billion in operations and maintenance costs. “Over 20 years, the savings would total about $30 billion,” the white paper argues.

The campaign began in December, soon after then-President-elect Trump criticized the “out of control” cost of the F-35 and then asked Boeing CEO Dennis Muilenburg to “price-out a comparable” F/A-18. In January, Defense Secretary Jim Mattis ordered a review that would look at how the Navy’s F-35C stacked up to a new, more advanced version of the F/A-18.

Boeing has used several names to describe its improved F/A-18, including Advanced Super Hornet, Block 3 Super Hornet, and F/A-18XT. (Here’s our own comparison of the single-engine F-35 and the twin-engine F/A-18 Super Hornet, or watch the video below.)

Boeing has been touting the improved Super Hornet to Navy officials for years, refining the proposed design over time, one source said.

“In 2013, we flew the Advanced Super Hornet with the intent of creating as stealthy as an aircraft as possible,” Jeff Johnson, vice president of business development for Boeing Military Aircraft, told reporters Tuesday at the company’s defense headquarters in Arlington, Virginia. “As we re-evaluated and looked closely at the evolving threats, the way the air wing of the future was developing, we steadily evolved and matured our thinking to develop the Block 3 Super Hornet, which focuses on the right things based on capabilities of other aircraft in the carrier air wing and what what the Navy told us they need to win in the next decade.”

At least one potential Trump administration leader isn’t convinced. During her confirmation hearing Thursday, Air Force secretary nominee Heather Wilson questioned whether an existing plane could be made stealthier .

But Boeing officials say the new Super Hornets would be less about stealth and more about balanced survivability. EA-18G Growlers — electronic jamming versions of the plane — are already planned to fight in concert with F-35s, degrading the enemy’s ability to track and target them. Boeing suggests that the Growlers could do the same for Advanced Super Hornets.

Lockheed is hardly conceding the battle. In an interview last week, Robert Rangel, the company’s senior vice president for government affairs, said he was hopeful the latest Pentagon review — ordered by Mattis — would favor the F-35.

Does Lockheed believe the F/A-18 is a viable alternative to the F-35C?

“We maintain that the answer to that is no,” Rangel said.

Rangel also pointed out that the carrier version of the Joint Strike Fighter is the variant with the fewest orders. Of the 2,443 jets eyed by the U.S. military, the Navy and Marine Corps only plan to buy about 350 F-35Cs.

“We feel pretty good about where the program is,” Rangel said. “It’s always going to be the subject of scrutiny just by virtue of the fact it’s the largest single program in the DoD portfolio and we recognize that. That means that we have to constantly be engaged and tell the story and make sure that we’re at the end of the day performing and executing.”

Lockheed has been quick to tout the falling price of the F-35 each year. The F-35C currently costs about $122 million.

Still, Boeing has spent years going after Lockheed’s F-35, albeit mostly for overseas orders. As part of a 2013 lobbying effort in Canada, a video emerged of two young brothers playing with model airplanes. One asks the other how he spent $10 from their grandfather. The boy responds that he bought an F-35 model. The other says for the same $10 he bought three Super Hornets with 10 years of Boeing maintenance.

In November, Canada said it would delay a decision to buy F-35s and would buy Super Hornets in the interim.

Earlier in September, Boeing said it would challenge Denmark’s decision to buy F-35s .

In February, when President Donald Trump visited a Boeing commercial airplane factory in Charleston, the new 787-10 Dreamliner was not the only topic of conversation.

"By the way, do you care if we use the F-18 Super Hornets?” Trump said. “We are looking seriously at a big order…The problem is that Dennis is a very, very tough negotiator, but I think we may get there."

At the end of his speech, he proclaimed: “God bless Boeing.”

During his visit, a pool reporter asked Trump about replacing F-35 orders with new F/A18XTs.

"If the price doesn't come down, we would,” he replied. “The F-18's a great plane and now put a stealth component onto it."

But Trump also said the F-35 program “was out of control and now it's very much in control .”

Regardless, the Navy is likely to buy more regular Super Hornets to address readiness shortfalls. The Trump administration has already asked Congress to approve $2.3 billion for 24 new Super Hornets.

Boeing hopes that orders after this are for the more advanced versions, while Lockheed hopes the money goes toward the F-35.