William O. Douglas,
Braniff Airways v. Nebraska State Board of Equalization and Assessment…
“ My understanding of our decisions is that the power to lay an ad valorem tax turns on the permanency of the property in the State. All the property may be there or only a fraction of it. Property in transit, whether a plane discharging passengers or an automobile refueling, is not subject to an ad valorem tax. Property in transit may move so regularly and so continuously that part of it is always in the State. Then the fraction, but no more, may be taxed ad valorem. ”
