itunes match????

Welcome to the Apple community.

When you turn iTunes match on, on your mobile device, you essentially start with a blank sheet, i.e. a list of all your iTunes items, but with non-of them actually your device.

As you select them and listen to them, they are downloaded and then stay on your mobile device. So when you are in an area where you have no connection, such as on a plane, the items that you are able to play, are the items that you have listened to and download since iTunes was first turned on.

If at any time you become short of space, you can delete items from your mobile device which will leave them in the iTunes list, so they can be re-downloaded again in the future.

Just a suggestion. What I do is this. I have a Playlist in iTunes of all the music I want to be on my iPhone. I switch off iTunes Match, sync with iTunes to get all the playlist stuff on, and then switch Match back on. That way, it means that I have all the music I want already on my iPhone, with all the rest available from iTunes Match.