I'm always perplexed by apps that have one component for a Linux-based operating system, Android, yet its PC component isn't available for Linux. Well, I ONLY use Linux--on every one of my laptops, desktops, tablets, and smartphones.
Sorry to say that AirDroid desktop client for Linux is not in the plan right now. But you can just open a brower on your Linux, sign in to web.airdroid.com and enjoy using AirDroid :D
Dear AirDroid Development Team, please stop sending us to the Web managment and just admit that Linux Client is needed. You made a great app but not having Linux native client is very disappoing drawback and you lose customers for the paid version. At least running via wine should be possible.