This will work as mentioned earlier, though "easy" and "complicated" might mean different things for each of us.
If "easy" means transferring file directly from a HD to another, this is for you.
But many people (and myself), would probably prefer it this way:
1) Do a time machine backup of your old computer (on another HD, or a time capsule...)
2) Restore the backup on the new computer: when you boot up OSX for the first time on the new Air, it will ask you if you have a time machine backup at hand.
The advantage of the above is that it is fully automated, there is absolutely no configuration to make or HD enclosure to open. It just takes a bit more time, but that's time you can spend having a drink, not clicking on buttons sorting your files
Time Machine restores everything, from programs to files (though you can make exceptions if you play with the backup options). In the worst case, some paid software suits may ask for your license key on the new Air on the first launch.