You might want to take a look at these two additional packages - they don't support iPad but will allow you to use your Air in conjunction with your desktop.
Both are virtual KVM software that allow multiple computers to share a single (or multiple) keyboard mice
ShareMouse is the more advanced software and it will let you use the Mouse/Keyboard from all connected computers - as well as it supports dragging a file from one computer to another. Its probably the one I'd recommend as I have used both at work where I have a single keyboard/mouse I use for both a windows & mac machine
Synergy is less advanced but costs less money and also will run over UDP & TCP which allows you to tunnel it though networks
Synergy can also be obtained for free if you want NO support by getting the nightly build at: https://synergy-project.org/nightly
These programs will also allow you to MIX operating system so you can share 1 mouse/keyboard between a Windows Desktop and a Mac Laptop for instance.
- ShareMouse - Costs more but is easier to use and more advanced
- Synergy - Costs less / free - harder to setup and limited to 1 "control" keyboard/mouse