The number of aerial tankers in the US military—ranging from Air Force KC-135s to Marine Corps KC-130s—will peak in Fiscal 2016, according to the Pentagon’s newly issued Aircraft Procurement Plan for 2012-2041. The total tanker inventory will increase from 551 in Fiscal 2012 to 574 in Fiscal 2016, then drop suddenly to a steady-state level of between 535 and 542 aircraft through Fiscal 2021. The numbers reflect the retirement of some of the oldest KC-135s, delivery of USAF’s initial KC-46As, and adjustments to the marines’ inventory. (2011 Aircraft Investment Plan)
Contracts for F-35 airframes in Lot 18 and 19 should be signed in the spring, but an engine deal is still not in hand and could take months longer. The delays don't seem to be driven by anticipation of how the new Trump administration will influence the program.