The US Air Force wants the next-generation air refuelling tanker, called the KC-Z, to fly and reach its first operational capability by 2040.

The KC-Z will be the third and final phase of the Air Force’s decades-long capitalization effort. The Air Force is currently commissioning the KC-46 Pegasus tanker fleet, the first phase of modernization, and wants to begin preparations for the next phase, called KC-Y.

According to DefenseNews, the Air Force predicts that the KC-Z will reach the Initial operating capability (IOC) by 2040. Explaining how these tankers would work in combat, the Air Force asked industry to explain how their aircraft would deal with the threats that could arise within a decade and reduce the risk for combat refuelling aircraft.

In the Air Force’s Climate Action Plan, released in October 2022, a photograph of the X-48B, an experimental mixed-wing prototype aircraft developed in the late 2000s by Boeing Phantom Works, NASA, and the Air Force Research Laboratory, indicates a future tanker or aircraft carrier. It was an example of the kind of model that the mobility aircraft could be inspired by.

In a debate at the Council on Foreign Relations on January 11, Air Force Secretary Frank Kendall said the mixed-wing design is still one of the key candidates for the next generation tanker or transport aircraft, but it’s too early to tell what the Air Force will end up with.

As the Air Force moves to modernize its tanker fleet in the coming years, it is not yet clear what its budget will be. John Venable, a senior defence expert at the Heritage Foundation, said budgetary issues could prevent the KC-Z tanker from reaching the IOC before 2040, despite growing concerns about the possibility of a war with China. “When I think about the timelines for KC-Z, I think it’s more budget-based than strategy-based,” Venable said.