Why Delta is dumping duty-free buying

Say goodbye to the high-in-the-sky duty-free club.

For travelers used to buying Cross pens and Fendi sunglasses duty-free while on Delta Air Lines (DAL) flights, get ready for a bumpy ride: The carrier has broken off its business relationship with its duty-free vendor.

Delta said the service was ended Friday after "the airline and its vendor were unable to agree on terms to continue to administer the program," according to a Delta statement. While duty-free shopping is a big business in airports, it remains a small business for airlines, which rely on such ancillary revenue for 5 percent of overall sales, according to Frontier Magazine.

The airline isn't looking for a replacement service, and there's some evidence that Delta wasn't selling a significant amount of duty-free items, according to Runway Girl Network.

As airlines add WiFi to their planes, airline executives are concerned that customers may increasingly migrate to buying goods from Amazon (AMZN), according to TR Business. Duty-free was offered only on Delta's international and Asia flights, excluding trips to the Caribbean, Runway Girl Network notes.