If a majority of all the votes cast upon the question shall be for the levy of the tax, the county board of such county shall thereafter annually levy such tax in the amount certified as necessary by the Commission but not to exceed the rate stated on the ballot, on all taxable property of such county, such tax to be levied and collected in like manner with the general taxes of such county and to form when collected, a fund to be known as the “County Airports Tax Fund” which said tax shall be in addition to all other taxes which such county is now, or hereafter may be, authorized to levy on the aggregate valuation of all property within such county, and the county clerk shall not consider this tax as authorized by this Act, as a part of the general tax levy for county purposes, and shall not include the same in the limitation of 1% of the assessed valuation upon which taxes are required to be extended.
     If a county has adopted a proposition for the levy of a tax of less than 2 mills on the dollar, such tax may be increased to a rate not to exceed 2 mills on the dollar, by submitting the proposition to increase such tax to the voters of such county in the same manner as the original question was submitted. Provided, however, that the foregoing limitations upon tax rates may be increased or decreased under the referendum provisions of the General Revenue Law of Illinois.
     The “County Airports Tax Fund” shall be used only for the purposes stated in the resolution calling the election authorizing the levy therefor.