A person desiring to erect a structure, or increase the height of a structure, or permit the growth of a tree, or otherwise to use the person's property in violation of airport zoning regulations adopted under this chapter may apply to the department for a variance from the zoning regulations. Variances shall be allowed where a literal application or enforcement of the regulations would result in practical difficulty or unnecessary hardship and the relief granted would not be contrary to the public interest but would do substantial justice and would be in accordance with the spirit of the regulations and this chapter.