All contracts for the acquisition, construction, development, improvement, operation and maintenance of airports, or other air navigation facilities, made by the department of transportation, either as the agent of the state or the agent of any political subdivision, shall be made pursuant to the laws of the state governing the making of such contracts, except that, where the acquisition, construction, development, improvement, operation and maintenance of any airport or other air navigation facility is financed wholly or partially with federal money, the department, as agent of the state or any political subdivision thereof, may let contracts in the manner prescribed by federal authorities, acting under the laws, rules or regulations of the United States, and in the manner prescribed by the charters of the charter cities of the state, notwithstanding any provision of state law to the contrary.