Bsi Holdings, LLC, Plaintiff/appellee v. Arizona Department of Transportation, Defendant/appellant.

Summary

The court held that the meaning of "day" under the aircraft license-tax statute cannot be determined apart from the meaning of "based in" Arizona. It rejected both the view that any momentary touchdown constitutes a taxable day and the view that a day necessarily means a full midnight-to-midnight period, and remanded for the tax court to determine the aircraft's Arizona base and calculate the applicable days. If the statute remains ambiguous after other interpretive tools are exhausted, the ambiguity must be construed in favor of the taxpayer.