WASHINGTON — Raytheon has been discussing the T-X trainer replacement program with the US Air Force for months, and has had conversations about joining the Alenia Aermacchi T-100 bid as prime contractor, Defense News has learned.

Alenia is offering its M-346 trainer for the T-X program and rebranded the T-100 as part of a joint offering with simulation firm CAE. General Dynamics had been part of that offering as the prime contractor until March, when it surprisingly dropped off the team.

Brig. Gen. Andrew Croft, director of Plans, Programs, Requirements and Assessments at Air Education and Training Command (AETC), and Col. Philip Wielhouwer, chief of AETC's Capability Requirements Division, revealed during an exclusive interview Monday that the Air Force has been discussing the program with Raytheon since around May of this year, two months after GD split from the offering.

"Raytheon's involved because they came to us, saying they were thinking about aligning with one of the contractors," Wielhouwer said. "This was in the spring of this year. We invited them to our pre-solicitation conference, which was held at Wright-Patterson Air Force Base in May."

Croft added: "They build a lot of components that could possibly make up components of an aircraft. I think they just want to stay engaged."

Notably, however, both men said the service was talking directly only with prime contractors and not subcontractors involved on any of the competitive teams.

Wielhouwer added that Raytheon hasn't withdrawn from the competition, and so the Air Force has continued to invite them to industry events related to the T-X. That includes a recent industry day immersion held in September for new AETC commander Lt. Gen. Darryl Roberson, where all competitors for the T-X contract presented.

AETC has emphasized transparency in its relations with industry as the T-X program has moved forward, with Croft saying the flow of information between the service and the various companies needs to be "fair and equitable."

An industry source with knowledge of the situation said that Alenia and Raytheon have had ongoing talks about the possibility of joining forces for a T-X bid. The source was not clear if a final agreement had been reached. Italian sources, meanwhile, have hinted for some time that a new prime for the T-100 bid is in the works.

Since GD's withdrawal, Alenia has continued to promote the T-100 as an option for the Air Force. But industry consensus has been that without a US prime, the Italian company was unlikely to fight off its competitors.

Raytheon, the fourth largest defense contractor in the world, has a portfolio largely focused on providing electronics, sensors and weapons to other contractors, rather than producing airframes. However, the fact the M-346 is a platform already in production could make this an attractive program for the company.

The winner of the T-X competition will provide the Air Force with 350 new aircraft to replace the aging T-38 fleet used for advanced jet training. The service believes a new trainer is needed not just because of the age of the T-38 fleet but because it cannot provide ample training for pilots who will be flying the F-35 Joint Strike Fighter in the future.

Grabbing the T-X contract will also provide the winning company an inside track to any number of international customers, especially given the prevalence of the F-35 around the globe

The Air Force's order could grow by 200 aircraft if the service decide to do away with the T-1 Jayhawk, used to train airlift and tanker pilots, and go to a single training aircraft.

Croft said that decision has not been made, and is probably "a ways off. … We're not going to wait around for years to make that decision."

Competitors include a pair of clean-sheet designs being put forth by a Boeing/Saab team and a Northrop Grumman-led coalition that includes BAE Systems and L-3; Textron AirLand's new Scorpion design; and the T-50, the Lockheed Martin/Korean Aerospace Industries offering.

The two Air Force officials confirmed that the schedule remains on track for a request for proposal to come in September 2016, a contract award in fall of 2017 and IOC coming sometime in 2023.

Croft said that he does not see the potential for a continuing resolution to impact the program, noting the RFP is "really independent of the budget discussion. … It's a requirement, we set the date and we'll move on from there."

Spokesmen for both Raytheon and Alenia declined to comment for this piece.

Lara Seligman in Washington and Tom Kington in Italy contributed to this report.

Twitter: @AaronMehta