I do not understand it! Recently I get on an airplane without Wifi and I follow their instructions to switch off the phone during take off. What I do is put the phone into airplane mode and then shut it off so that when I turn it back on there isn't any transmission.
So I do all this and try to listen to Spotify in the 9hrs 30 minutes of the flight and guess what YOU CANT. You open Spotify App and it requests to connect to facebook website so you can login.
I have been contacting "Spotify Support" And they can't help or explain at all! So can anyone explain how Spotify can work without an internet connection without having to know in advance? I don't understand why I pay for the service and they claim for "offline sync" if the app itself can not cope with being offline and disconnected from the network.