When I was in SXM I left my Verizon serviced Galaxy S7 phone in airplane mode and just turned on wi-fi. I needed to call home and we were not within wi-fi reception so I had to take it off airplane mode to make the call. I left it out of airplane mode the rest of the day and texted. Since it is for a 24 hour period I figured I'd use my hone as usual and I made sure to go back to airplane mode before the 24 hour period expired. My next month's bill showed only the additional $10 charge.