Hello, haven't flown for a while... and now a friend made reservation in my name. When I check in my suitcase and pay with a different credit card (different name), will this cause a problem? I have that fancy ID, and a current passport, and this is a domestic flight on Delta, round-trip.

Do I understand that your ticket is already paid for? And you will just want to pay for your checked bag when you go to check in online?

I don't think it will be an issue as long as you have the confirmation code. I would do it online in the 24 hour window just in case you have a problem, you should be able to fix it at the airport.