What he is saying is that roaming only covers ground charges, there will be chaarges for using the airlines system to make calls, so if you don't turn airplane mode, chances are you will have an enormous data bill from the network running in the background.
ubiquitous_uk t1_ixr0fx4 wrote
Reply to comment by Bumwax in Bye-bye airplane mode: EU allows smartphones during flights by Zhukov-74
What he is saying is that roaming only covers ground charges, there will be chaarges for using the airlines system to make calls, so if you don't turn airplane mode, chances are you will have an enormous data bill from the network running in the background.