Maryland Code, Transportation § 5-607

(b)(1) Airport zoning regulations and boundaries of airport zoning districts are not effective until there has been a public hearing at which interested parties and the public have an opportunity to be heard.

(2) At least 15 days' notice of the time and place of the hearing shall be published in a newspaper of general circulation in each of the political subdivisions in which the airport is or will be located.

(c)(1) Any regulation and boundary may be amended or repealed from time to time. However, if the owners of at least 20 percent of the area included in a proposed change sign a protest against the change, the change is not effective unless approved by two thirds of all the members of the joint board or of the legislative body of the political subdivision, as the case may be.

(2) Subsection (b) of this section on public hearings and notices applies to all changes made under this subsection, and, if the change is in a boundary of any airport zoning district, notice of the hearing also shall be posted within that district, at the place that the zoning authorities designate.