Federal lawmakers have delayed the U.S. Air Force’s plan to establish an aggressor unit flying early-model F-35 stealth fighters. Aggressors portray the enemy in aerial war games.

“The draft 2020 defense policy bill prohibits the Air Force from transferring any low-rate initial production F-35s to the adversary air role until the chief of staff submits a report to Congress detailing the service’s plan for modernizing its organic aggressor fleet,” Amy McCullough reported at Air Force Magazine.

The Air Force still could get its stealthy aggressors, but Air Force chief of staff Gen. David Goldfein first must submit a report to lawmakers.

The law requires the report to detail “potential locations for F-35 aggressors, including an analysis of installations that have the size and availability of air space necessary to meet flying operations requirements; have sufficient capacity and availability of range space; are capable of hosting advanced threat training exercises; and meet or require minimal addition to the environmental requirements associated with the basing action.”

In addition, Congress requires Goldfein to lay out the Air Force’s vision for its existing aggressor force, which includes two squadrons that fly F-16s.

Representatives are interested in the Air Force’s plans for “upgrading aircraft radar, infrared search-and-track systems, radar warning receiver, tactical data-link, threat-representation jamming pods and other upgrades necessary to provide a realistic advanced adversary threat.”

The Air Force in May 2019 announced it would re-establish a defunct F-15 aggressor squadron to operate the roleplaying F-35s. The service in 2014 shuttered the 65th Aggressor Squadron as a cost-saving measure.

The 65th Aggressor Squadron in its new form would operate nine early-model F-35A stealth fighters that the Air Force considers unsuitable for combat. The “red air” F-35s would help the Air Force to copy the tactics of Russian and Chinese squadrons respectively flying Su-57 and J-20 stealth fighters.

The unit would require 194 military personnel and 37 contract personnel plus an additional 60,000 square feet of facilities and 300,000 square feet of ramp space at Nellis Air Force Base in California, Col. Travolis Simmons, commander of the 57th Adversary Tactics Group, told McCullough.

The 65th Aggressor Squadron’s F-35s, which currently are with a training unit at Eglin Air Force in Florida, may be some of the least capable of the Air Force’s roughly 200 F-35s, but they still represent a major upgrade for the service’s aggressor force.

“The F-35's ability to play the bad guy will surpass that of any aircraft ever tasked with the mission before,” The War Zone editor Tyler Rogoway wrote.

The aircraft is uniquely suited to replicate a wide range of threats with unprecedented high fidelity. I have talked with sources about this in the past and they have noted that the F-35's software alone should be able to be manipulated to replicate the sensor, sensor fusion, electronic warfare and communications capabilities of adversary threats.

In other words, applications could be designed to limit various aspects of the F-35's capabilities—and enhance others synthetically via data-link—to better mirror that of the aircraft it is masquerading as. In addition, it can be equipped with bolt-on radar reflectors that may be able to be manipulated to better replicate certain radar signatures of enemy aircraft, including those that aren't even stealthy at all.

Once the 65th Aggressor Squadron stands up, the Air Force will have three dedicated red-air units. The 64th Aggressor Squadron flies F-16s from Nellis. The 18th Aggressor Squadron and its F-16s are based in Alaska.

The U.S. Navy and Marine Corps have their own adversary squadrons flying F-16s, F/A-18s and F-5s. The Air Force, Navy and Marine Corps also contract with civilian companies such as Draken for red-air services. The Air Force has launched a $6-billion program to hire civilian aggressors to fly from 22 bases across the United States.

The Air Force isn’t waiting for the 65th Aggressor Squadron to form before it sends F-35s to portray enemy planes. For two weeks starting in late April 2019, F-35s from the active-duty 388th Fighter Wing and reserve 419th Fighter Wing played the part of enemy fighters in a wide-ranging war game at Hill that also involved Air Force pilot trainees flying F-16s as well as adversary planes from Draken.

The F-35s alongside F-16s and Draken’s own planes played the part of the enemy force. “We flew 100 F-35A missions with 22 aircraft, integrated on 56 F-16 missions and defended vulnerable assets for a 16-hour window,” the 388th Fighter Wing stated on social media.

The “blue force” F-16s outnumbered the “red force” F-35s, F-16s and adversaries. “We were severely outnumbered,” said Maj. Thomas Meyer, a weapons officer with the 388th Fighter Wing. “We had a five-to-one aggressor ratio and we were tasked with defending a list of assets over an eight-hour tour time block. We had aircraft sitting in alert status to respond to whatever enemy threats were presented.”

Maj. Benjamin Walters, an F-16 instructor pilot, praised the F-35 pilots playing red air. “These guys are getting really good at flying the F-35 and they can present some aggressive situations that force young pilots into errors,” Walters said.

David Axe serves as Defense Editor of the National Interest. He is the author of the graphic novels  War Fix, War Is Boring and Machete Squad.