Originally Posted by
Yoshi212
As a fellow traveler I cannot implore you more to not use a voice service while on a plane if texting is possible.
Skype, Signal, Facebook Messenger and a bunch of others work over wifi.
Intercom is for Android via wifi and bluetooth.
Agreed on avoiding voice if at all possible.
Skype seems to require internet, which is what I'm trying to avoid for use in flight. Signal also seems to require internet. Intercom for Android doesn't need internet, but it also is voice-only. People complain big-time about Firechat's ads and battery usage.
Possible solutions that I plan to try are Bluetooth Messenger by MaxDotA and Bluetooth Chat by Emparador.
LATER:
Bluetooth Messenger seemed OK, although it did not seem to do any sort of Notification when a text came in. After some experimenting, it began sending gibberish instead of text...re-starting the app in both devices solved that issue. The premium version costs $3.99. The lack of notification seems to be the big issue.