cannot access itunes when internet is not available

So, I'm cruising down the road listing to my music via Bluetooth from my iphone. I decided to change to another artist. so I pick up my phone and press the iTunes music icon. and nothing happens. I just got a blank screen. My phone acts like it is looking for the internet. this is the second time it has happened. I don't believe it is a safety feature because it seems to work alright when I have cell service, but, if I am out of the service area it doesn't work. anyone got any ideas?