But they just added sound to "ae" and that sounds like "eye". So would the two words only be told apart by context in a sentence, or is "ai" pronounced slightly different than "ae"?
They do sound very similar and the difference is subtle. I hope you get a chance to hear them next to each other. To my ear ’ai sounds sharper and ‘ae sounds flatter, but I don't know if that will mean much to you. When saying them, finish ‘ai with more of an ee sound, and finish ‘ae with more of an ay (like the name of the letter A) sound.