A song can be catchy, if hearing it makes you want to keep singing it. Anything can be attractive if it has desirable. For example a commercial offer can be attractive. If a person is attractive, that usually means romantically desirable. A person can be "a good catch" if they are desirable as a boyfriend, girlfriend, husband, wife etc.

"Catchy" is only for songs and things you say (words, phrases, etc.). "Attractive" can describe anything that looks or sounds good.

So, attractive means good looking, pretty, nice to look at, all of those types of qualities. When something is attractive it is appealing to the eye. Catchy usually refers to a jingle or song. So if something is catchy, it's memorable in a way.