Section 51I. The airport commission of any city or town shall be authorized to expend any funds granted to, or received from any source or appropriated by, such city or town for airport purposes and may make contracts for the maintenance, operation, construction, enlargement and improvement of the airport and for the purchase of materials, supplies and equipment pursuant to the laws of the commonwealth governing the making of like contracts; provided, that where such maintenance, operation, construction, enlargement and improvement of the airport, and purchase of materials, supplies and equipment, is financed wholly or partly with federal moneys, the airport commission may act in the manner prescribed by the federal authorities, acting under the laws of the United States, and any rules or regulations made thereunder, notwithstanding any other law of the commonwealth to the contrary.