Before buying a plan, Delta in-flight wifi allows you to send DNS packet to the whole Internet, and allows you to send HTTP/HTTPS traffic to some specific hosts:
v.whatsapp.net [Speed Limited]
Then it's easy to get a solution! iodine is a ultimate solution but it's extremely slow. The easiest solution is v2ray, which widely used by chinese guys to fuck the fucking GFW.
Assuming that you already know how to use v2ray. You can learn how to use v2ray from any "breakwall" service provider.
1 - Setup a v2ray server
You are recommended to use
vmess+http2+tls and some other protocols also work, but let's start with the most common one:
2 - Install v2ray client on your phone / laptop
Android phone please install
v2rayNG from google play store. There are hundreds of clients designed for Windows/Linux/MacOS/iOS/Android, and it's your own responsibility to find one.
After filling your server information into your client correctly, you need to modify some of them. You must modify "request host" to
www.paypal.com, modify "SNI" to
www.paypal.com, and set "allowInsecure" to
true. Make sure your "server address" is still correct, and you only want to modify the SNI & host.