For every 10 people flying any given Delta Air Lines flight, just four are members of the Airline’s loyalty program, SkyMiles.

A stat like that underscores the opportunity for the airline to grow its first-party data and provide a rich in-flight experience. One way it’s doing that is by offering free Wi-Fi and other in-flight entertainment options for SkyMiles members.

According to Delta CMO Tim Mapes, “40% of any given plane are SkyMiles members, 60%, therefore aren’t, which is a huge growth opportunity,” he told Adweek following Thursday’s announcement here at CES.