I'm installing from DVD disks which is taking forever do I have to download updates before I can start flying.

It will auto-update as soon as you load. It checks for updates every time, as does the download version.

Can I start flying while it updates it's self on first launch.

It is about a 20GB update and you have to wait until it has installed before flying the sim  

Paul

Thanks won't be today then.

After it's finished can you confirm that DVD disc is no longer needed in the drive in order to play? I'd like to have confirmation of the info from another user/thread.

From a post by Mathijs KoK Aerosoft

1. The DVDs contain only the installer and the content (aircraft, world etc). The actual simulator software is downloaded during installation. That way you always have the latest version. For this the installer will guide you through the creation of an Xbox account (if you do not have one) etc. That means you need an active internet connection during installation. You also need a connection to run the simulator (it updates itself at every start when needed). But to be frank, it makes very little sense to run this offline.
2. After you ran the DVD installation, you will be asked to re-insert DVD 1. This will be checked during the activation.
3. At the first start the sim will check all files and update everything that is needed.  As time progresses this will be a larger download.
4. From the users perspective you will end up with exactly the same version as somebody who bought it at the Microsoft Store.

Keep in mind that the sim consists of four parts:

1. The simulator itself, obviously mandatory.
2. The default content (basic world, aircraft etc). This default world is on it's own far better then FSX could ever deliver. This is a mandatory part, always part of the simulator..
3. The downloaded content (more details for the world, better ground imagery, far more correctly placed trees etc etc). This comes in 'blocks' that can be buffered on your system so if you always fly from Detroit it will not have to be loaded every time). Contrary to what some less informed sources say there is absolutely NOTHING indicating this is paid content or will be paid content. We do not sell a time limited simulator.  This is an optional part, you do not have to stream any scenery, weather or traffic.
4. Third party content that can buy from the build in store or from external shops. Obviously optional, it is a super sim without add-ons.