The Secretary of the Navy may construct or acquire family housing units (including land acquisition and supporting facilities) at the installations or locations, in the number of units, using amounts appropriated pursuant to the authorization of appropriations in section 2204(a) and as specified in the funding table in section 4601. (b) Planning and design The Secretary of the Navy may carry out architectural and engineering services and construction design activities with respect to the construction or improvement of family housing units using amounts not to exceed amounts appropriated pursuant to the authorization of appropriations in section 2204(a) and as specified in the funding table in section 4601. 2203. Improvements to military family housing units Subject to section 2825 of title 10, United States Code, the Secretary of the Navy may improve existing military family housing units in an amount not to exceed the amounts appropriated pursuant to the authorization or appropriations in section 2204(a) of this Act and available for military family housing functions as specified in the funding table in section 4601. 2204. Authorization of appropriations, Navy (a) Authorization of appropriations Funds are hereby authorized to be appropriated for fiscal years beginning after September 30, 2019, for military construction, land acquisition, and military family housing functions of the Department of the Navy, as specified in the funding table in section 4601. (b) Limitation on total cost of construction projects Notwithstanding the cost variations authorized by section 2853 of title 10, United States Code, and any other cost variation authorized by law, the total cost of all projects carried out under section 2201 of this Act may not exceed the total amount authorized to be appropriated under subsection (a), as specified in the funding table in section 4601. XXIII Air Force military construction 2301. Authorized Air Force construction and land acquisition projects (a) Inside the United States The Secretary of the