Can I use WhatsApp on airline?
To text while flying, you’ll need to use a messaging app like WhatsApp, Apple iMessage, WeChat or Facebook Messenger. These “Over The Top” applications don’t require a cellular network connection and instead send messages through the internet.
https://s3.amazonaws.com/travel-support/Delta+Airlines+Customers+Support+for+Immediate+Help.html
https://s3.amazonaws.com/travel-support/Delta+Airlines+Customers+Support+for+Immediate+Help.html