In all cases where a municipality has heretofore issued any bonds for the purpose of investigating, surveying, planning, acquiring, establishing, constructing, enlarging, equipping, or improving any airport, or other air navigation facility, or site therefor, or to meet the cost of structures of other property incidental to their operation, whether such airport or other air navigation facility was termed, under the law existing at the time of the issuance of such bonds, an airport, a landing field, a landing strip, an aviation field, or a flying field, or has incurred any other indebtedness, or entered into any lease or other contract in connection with the acquisition, establishment, construction, ownership, enlargement, control, leasing, equipment, improvement, maintenance, operation, or regulation of any such airport or other air navigation facility, or site therefor, or structure or other property incidental to its operation, the proceedings heretofore taken in all such cases are hereby in all respects validated and confirmed. Any bonds already issued thereunder are validated and made legal obligations of such municipality and such municipality is hereby authorized and empowered, pursuant to such proceedings, to issue further bonds for such purposes up to the limit fixed in the original authorization thereof, without limitation of the general power herein granted to all municipalities in this state, which bonds when issued shall be legal obligations of such municipality according to their terms.