Thanks again guys.
I think I'm gonna settle for the GoPro due to its versatility, and will take a look at that skeleton case with the filter.
However, I am still concerned about connection to the aircraft intercom. I appreciate how it may take some experimentation to get the volume level right, however, I am more worried about the possibility of damage to the camera's mic input circuitry due to too strong a signal from the aircraft intercom output. I'm guessing the impedance will be a lot lower than that which is typical for aircraft speakers/headsets?