I'm no radio expert but there have been many post on interference issues flying around marinas and boats in general. They may have a variety of signals emanating from them like WIFI, GPS, and all internal combustion engines--cars, trucks, real airplanes and many trains--are spark gap generators. They do not transmit any one frequency, but they can mask whatever frequency you are transmitting on. If a jumbo jet or military fighter flies over the area where you are flying your RC airplane, or even if a train goes by, your signal can be masked long enough to crash your RC. Maybe someone with radio expertise will comment here to clarify.