Even more improvements have been requested for RAF Fairford in the FY2019 program under European Defense Initiative (non-RC-135 related):
Flight Line Munitions Holding Area: $19M
Deployable Air Base System - Facilities, Equipment & Vehicles (DABS-FEV) Storage Complex (would free up an aircraft hangar and replaces 2 x old leaky non-environmentally controlled "Rubb" shelters): $87M
Source:
https://www.google.com/url?sa=t&rct=...SdDVTtpQDDU0B6 Pages 214-219