Example:
Don't say ''aren't I'', it's incorrect. I'm in my car, am I not?

Example:
Don't say ''ain't I''. ''Aren't I'' is correct. I'm in my car, aren't I.

Example:
For example, you DO NOT say "I ARE going to the party," but rather "I AM going to the party." If you say "I ARE going to the party" you are using the word "are" in the first-person singular instead of the word "am" which is incorrect. In the same way, when you say "Aren't I" you are using "are" in the first-person singular when you should be using "am." Thus "Aren't I?" is incorrect.

Another example: "I'm still invited to your party, aren't I?" This is WRONG because this person has used "are" in the first-person singular. He or she should have used "am" instead. It would have been correct if this person had instead asked, "I'm still invited to your party, am I not?" or "I'm still invited to your party, right?"

For those who are still unconvinced, remember that I have given grammatical and logical reasons as to why "Aren't I?" is incorrect. If you still want to argue that it is correct just because a lot of people tend to use it then I would point out to you that your argument is an ad populum argument. Just because a lot of people might believe something is correct that does not in and of itself make it correct. A lot of people used to believe the world was flat but that did not make them right. No, they were still wrong, just as people who think "Aren't I?" is correct are still wrong even if there might be a lot of them who think it is correct.

Example:
1) - U.S.A.: "who else have you bombed, afghanistan?"

- Afghanistan: "who haven't i bombed?"

2) -Jim: "God dammit, who here else has fucked my girlfriend?"
-Dan: "Honestly Jim, who hasn't fucked your girlfriend?

3)-Man 1: "What are you doing?"

-Man 2, interjecting: "I think the correct question would be what aren't i doing?