No person in an aircraft shall throw out, drop or deposit within the city any litter, handbill or any other object. No person, except a duly elected or appointed officer or employee of the city while acting within the proper authority of such office or employment, shall post or affix any notice, commercial or noncommercial handbills, poster or other paper calculated to attract the attention of the public, to any lamppost, public utility pole or shade tree in a public place, or on any public structure, except as may be authorized or required by law. (1986 Code)