Air Smiles, don't fret my friend. I instructed a guy a few months ago in a C180 who had hearing aids in both ears. Whilst your medical standards are probably different to those where I am (NZ), there is usually no problem with people flying dual or with a safety pilot. Interestingly, this guy was holding a medical. The only restriction on this guy's medical (apart from wearing the hearing aids), was that all electronic devices apart from the radio and transponder had to be switched off.