You say you have your hearing aids paired with your iPhone? On mine (Resound Hearing Aids) there is a feature in the Resound iPhone app called Live Listen. It essentially uses the iPhone's microphone for the input for the hearing aids. If the person traveling with you were holding the iPhone, with Live Listen activated, you might be able to hear that person better. That's the theory, anyway. When i've used Live Listen I have found the audio quality to be sort of echo-y. It might be something you can get used to so that you don't notice it so much.
-Speak