100% This. Until the "free" wi-fi can handle a large number of the passengers streaming video (while not dropping a ton of packets for those on VPNs or other connections) it is a dubious proposition and marketing fluff.
I don't see that happening inside of 10-15 years. This is still a satellite based connection and the bandwidth available is growing slower than or at best equal to the rate at which people normally consume data on their devices. Best solution is to just charge for data by volume used, after giving a certain nominal amount for free. But the system really has to be setup for that. Currently, I'm pretty sure the authentication is by MAC address, and MAC addresses an be easily spoofed. They'd need to give each person a separate PSK from which a PTK can be generated, and somehow tie that to wifi access, so that someone sitting 5 rows from you can't sniff and then spoof your MAC address and use the data you paid for.