No policy of insurance issued pursuant to this chapter may be canceled or terminated, except for nonpayment of premiums, until at least thirty days after notice of cancellation or termination of said policy of insurance has been filed in the office of the Department, except that a subsequent policy procured and certified to the Department shall on the effective date thereof terminate the insurance previously in effect with respect to any airport designated in both policies. If a policy is canceled for nonpayment of premiums, notice of cancellation shall be filed in the office of the Department.