WASHINGTON (AP) — President Donald Trump is ordering the U.S. Navy to remove the advanced system used to launch fighter jets from its newest type of aircraft carrier and return to using older steam catapults that he has long said he prefers, according to a directive issued Thursday.

The new mandate would likely cost billions of dollars and revert the Navy’s most advanced ships to a system that takes more sailors to operate and is more difficult to maintain.

The memo directs the Pentagon and the Navy to present Trump with plans to remove the Electromagnetic Aircraft Launch System, also known as EMALS, within two months. It also says the Ford-class carrier’s electromagnetic weapons elevators should be replaced.

The move comes after years of Trump railing against the new, magnetically powered catapult system that shoots fighter jets off the deck of the carriers. It also comes at a time when the U.S. military is trying to find funding from Congress for all its desired equipment and as the Navy is struggling to fill its ships with enough sailors.

Trump’s ire with the new technology goes back to at least 2017 in his first term, when he claimed the new system is “not good” and “doesn’t have the power” of the older, steam systems in an interview with Time magazine.

“You’re going to goddamned steam,” Trump said at the time. The topic has frequently come up since then at rallies and other events.

While Trump is looking to roll back the latest technology, the newest Chinese aircraft carriers employ electromagnetic catapults and France said it plans to use the system on its new carrier.

Trump’s memo directs the fourth Ford-class carrier, the USS Doris Miller, to be the first ship to include the new changes. That will leave the USS Gerald R. Ford, as well as the forthcoming USS John F. Kennedy and USS Enterprise, untouched.

However, redesigning an already finalized ship for such a major system change will not be an easy task.

General Atomics, the company that makes EMALS, told The Associated Press in an email that the decision not to proceed with the system on the USS Doris Miller “warrants careful reconsideration.”

Trump’s memo that mandates the removal of the system also noted that one of the issues facing shipbuilding is the Navy’s constant design changes, “which have resulted in cost growth, delays, and cancellations.”

General Atomics said the work on the Doris Miller’s catapults and arresting gear was already halfway complete and said “changing course now would introduce significant cost, schedule, and integration risks.”

The move comes as Congress will weigh the necessary budget and funding bills that the Trump administration has said they need to fund the Pentagon and the Iran war.

Defense Secretary Pete Hegseth estimated last month that the war’s cost grew to $37.5 billion as Republicans prepared a $95 billion package to fund the military, along with other White House priorities.

Hegseth said the supplemental war funding is an “urgent, necessary” injection of money, and with Trump’s proposed $1.5 trillion defense budget a generational investment in the military.

The House narrowly adopted both but the Senate still must act when it returns in September.

Some of the key advantages to the electromagnetic system are its ability to launch aircraft at faster speeds while being easier to maintain, requiring fewer sailors to operate and using less space aboard the ship.

EMALS aboard the USS Ford cut the number of sailors need to operate the catapults from about a dozen to two.

Reverting to a system that requires more people to operate it comes as the Navy has struggled to translate its recruiting successes in the past year to actually filling jobs on warships. At the start of the year, the Navy had about 20,000 unfilled posts across the fleet.

In February, the Navy touted the system in a press release that said it allowed the USS Ford to launch and recover aircraft at a higher rate than its predecessor, the Nimitz-class ships.