If AirVPN supports OpenVPN (it probably does), there is a way to have an OpenVPN connection that is not actively used unless you specify it for the app which you want.
For instance with qBittorrent you can select to use the VPN network interface in the settings. This has the nice advantage that it also acts like a kill switch.
It is a little bit finicky to set up for the average user, but if you have some basic tech skills it should be easy with the right guide. If you're interested I canl try to find it.
It's a PayPal alternative, but developed in tandem with most European banks. That way, it will at some point also be used as backend for your normal debit and credit card payments, instead of VISA / MasterCard. If I remember correctly.