When you say Easyjet, Ryanair etc, do you mean does it have the paint jobs for those planes or the actual planes that the airlines use?
If it's the planes the airlines you then it has the Boeing 737-800 which is all that Ryanair fly and it has an Airbus 321, which is very similar to the A319 that Easyjet mainly fly.
If you just want the planes to look like their real-life counterparts, then no they don't. They have made-up airlines so that Microsoft don't have to pay for any licensing rights.
However, you can download skins for your aircraft from numerous sites:
http://www.avsim.com is a good one to start from.
It is good fun, but you need to give it some time. You can just jump in a plane and fly around, but its not as much as fun as taking the time to learn how to use the autopilot and learn a bit about navigation and the suchlike. It's also a real resource hog and you'll need a top-end computer to make it look vaguely decent.