He's really fishing for this one
Is he of the "It's Not My Fault" generation?
If he sincerely believes that your plane cut off his signal, ask him if he'd like to buy some waterfront property in Florida....
He's totally off base with this one. Even if you two were flying formation, with your plane between his plane and the transmitter, that would not happen. 2.4 signals pass through foam quite nicely.