Hi Mark,
I see we came up with similar yet dissimilar theories at approximately the same time. I am believeing more, and more, that the Airions can build up in the pilot of time, and can be successfully transmitted, during flight, to the model, thereby displacing the Groundions present. Might could explain why Keith's and Billy's planes (among others) seem to never age over hundreds and thousands of flights........ ?? ?? ?? I am seeing a direct correlation between the pilot, his abilities (both native and trained) and the amount of successful airtime each has had as it compares to his or her ability to transmit said Airions to the model in flight.