Starting October 1, passengers on most Delta will have free access to WhatsApp, Facebook Messenger and iMessage. To access the feature, a passenger will have to log into Delta's in-flight wifi portal powered by Gogo. This is first time an airline has offered such a service throughout its fleet.
Traditional SMS messages will not work. Only the aforementioned mobile messaging services are supported at launch and users will not be able to send videos or pictures. Passengers are, thankfully, not able to use this service to live stream from their flight.
I fly a lot and this is a significant free service to me. Over countless flights, I purchased a costly Gogo internet package just to use iMessage. Most of the time in a flight I don't want to check my email or Slack or Twitter. When flying I want some me time, but sometimes, it's also nice to just chat with some friends and now that can be done for free.
Even before this, there was some hacks and workarounds to let users access these services without paying. Not that I'm the sort of guy to exploit such loopholes.