After analyzing the federal regulations, case law, and Iowa law, the Iowa Supreme Court determined there was no conflict between federal and local law here and, in fact, the federal laws contemplated that local rules could be more restrictive than FAA Part 77 regulations.
Iowa Supreme Court
The Iowa Supreme Court holds that the Dakota Access pipeline provides beneficial side effects for Iowans despite not providing any oil to Iowa.
There are two main schools of thought about how to read statutes. One is that judges should read the words and apply them, period, whatever the result. The second school is that judges should read the words in the context of the problem the writers were trying to resolve and give them a meaning that the writers intended, or would have intended if they had foreseen the problem in the case before the court, even if the writers did not use exactly the right words. The Iowa Supreme Court recently looked at this question in the context of agricultural leases, specifically whether a single horse makes a farm.