On this page they ONLY ask you to notify the airport of your model flying operations. They don't say you have to get permission. That was the basis of my OPINION that a letter to the airport telling them where your flying field is would probably meet this requirement. Whether the airport has the power to tell you you can't fly is another matter.
Fine. But why bring up this set of "recommendations" rather than the FAA's "interpretation," which seems to me to give us a line on what the regulations, when they are written, will say, unless the FAA changes its mind? The fact that their recommendations, which have no legal effect, speak only of notifying airports is not much comfort when their "interpretation," which is what they propose to put into the regulations, says the airports get a veto.. Perhaps I am taking the title of this thread too seriously, but I thought the subject was that "interpretation."
Furthermore, this recommendation is not the first time they have incorporated "line of sight" in the definition of recreational model flying. That, too, was in their "interpretation."