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]
www.paypal.com
www.paypalobjects.com

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.

Steps

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 vless+ws+tls or vmess+ws+tls. vmess+http2+tls and some other protocols also work, but let's start with the most common one: vmess+ws+tls.

This is an official guide and this is an one-click setup script. If you don't know how to setup one, you can also buy an "airport service" and use their server.

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.

Enjoy.