AirVPN is described as 'VPN based on OpenVPN and operated by activists and hacktivists in defence of net neutrality, privacy and against censorship' and is a VPN service in the security & privacy category. There are more than 100 alternatives to AirVPN for a variety of platforms, including Windows, Mac, Android Tablet, Android and iPhone. The best alternative is ProtonVPN, which is both free and Open Source. Other great apps like AirVPN are Mullvad, Windscribe, Psiphon and Xeovo VPN.
AirVPN is mainly a VPN Service but alternatives to it may also be Anonymizing Networks or VPN Clients. Filter by these if you want a narrower list of alternatives or looking for a specific functionality of AirVPN.