Haw. Rev. Stat. § 261-9: Contracts, law governing.

The department of transportation may enter into any contracts necessary to the execution of the powers granted it by this chapter. All contracts made by the department shall be made pursuant to the laws of the State governing the making of like contracts; provided that where the planning, acquisition, construction, improvement, maintenance, or operation of any airport, or air navigation facility is financed wholly or partially with federal moneys, the department may let contracts in the manner prescribed by the federal authorities acting under the laws of the United States and any rules or regulations made thereunder.