The U.S. Air Force is contemplating pursuing a low-end, light attack
“OA-X” aircraft to augment the A-10 Warthog in a close-air support
(CAS) role, while simultaneously aiming for a more robust replacement,
dubbed “A-X2,” down the line.
..... Simultaneously, the service is also looking into an “A-X2” as a long-
term Warthog replacement, the analysts said. Ideally, A-X2 would be
designed to operate in a　m o d e r a t e -　t o　l o w - t h r e a t
r e g i m e,　meaning that it could fight in some contested conditions.
The service officials left the door open as to whether A-X2 would be
an existing airframe or an entirely new aircraft, but noted that
a f f o r d a b i l i t y　and　s p e e d　to ramp would be critical.

A-10 Warthog Replacement:
　　　U.S. Air Force Considers Two-Step Approach
Jul 21, 2016 - Aviation Week/Aerospace Daily & Defense Report
ttp://aviationweek.com/defense/10-warthog-replacement-us-air-force-considers-two-step-approach