Under the F-35 joint program office’s latest plan, follow-on modernization for the Joint Strike Fighter could add up to a total of $16 billion, the Defense Department’s program head confirmed Wednesday.

Responding to questions from lawmakers about the price of implementing the new Continuous Capability Development and Delivery strategy, or C2D2, Vice Adm. Mat Winter acknowledged that U.S. and international customers could pay up to $10.8 billion for development and $5.4 billion for procurement of upgrades to the F-35 between fiscal years 2018 through 2024.