The change to cashless comes as many consumers are trying to cut back on their use of credit cards. But Delta said in a message to customers that the move helps to "expedite our onboard payment process."
Delta spokesman Paul Skrbec said it will mean increased "convenience and speed of transaction" for customers.
Accepting only credit cards also allows airlines to cut the need for flight attendants to handle and account for cash collected from passengers.
But what about passengers without credit cards, like children?
Skrbec said children flying with Delta's unaccompanied minors program, which costs an extra $100 each way, can get complimentary snacks.