Most credit card issuers, including Citi, have restrictions on who is eligible to apply for their personal and business credit cards. With American Airlines credit cards from Citi, you can only receive the sign-up bonus if you have not received a bonus on the same card within the last 48 months.  However, it is possible to have more than one type of American Airlines card. For example, if you already have the CitiBusiness / AAdvantage Platinum Select Mastercard or Citi / AAdvantage Platinum Select World Elite Mastercard, you are still eligible to apply for the American Airlines AAdvantage MileUp.