Hello,
Here is my hypothesis :
You can buy wings from time to time with cash shop event on New Frontier.
On Smugglers Paradise, you can only have wings through events (some players won wings with the PVP Olympian event last winter, if i remember well), as there is no cash shop.
So there is wings on both server, but the way to get them is different.
This is what i think, not an official statement

.