https://www.cnbc.com/2017/09/27/delta-free-text-messaging-service-goes-live-oct-1.html

Delta Air Lines said Wednesday that customers will be able to send free messages with popular chat platforms while in the air, beginning Sunday.

Customers will be able to use iMessage, WhatsApp and Facebook Messenger while in the air on a Gogo-equipped flight. Gogo is a popular Wi-Fi platform that costs money, but customers won't need to pay for access to send and receive messages on those three platforms. Standard SMS text messages, which use cellular networks, will not work.