Getting a travel rewards card is a great idea. These cards both come with high rewards on travel spendings. For example, you will earn 2x AAdvantage miles on American Airlines purchases with both cards, but the Citi® / AAdvantage® Platinum Select® World Elite™ Mastercard® credit card will also give you 2x miles at gas stations and restaurants. What is more, the Citi® / AAdvantage® Platinum Select® credit card offers 60,000 bonus miles after making $3,000 in purchases within the first 3 months of account opening. Another difference is in rate and fees of these credit cards. The Citi® / AAdvantage® Platinum Select® World Elite™ Mastercard® credit card comes with $99 annual fee waived for first 12 months.
Aviator credit card has higher rates and fees. This card offers up to 26.24% interest rate and $95 annual fee since the first usage year. You can't choose which one you apply for. We also recommend you consider other credit cards for travel. Some of them comes with no annual fee and interest free period.