Can I use my Iphone as normal phone?

Without a plane, yes.
Without a plan, no.
(At least I don’t know how you could.)

Planes are not required for use of the iPhone. However I doubt you can without a plan.

Apple (hence, iPhone’s) contract with AT&T is up soon – wait a few months and you might be able to use your current provider with your iPhone. You could even call your service provider and ask if they’re going to start supporting the iPhone, and if so, when they think that service will be available. Of course, be prepared to be a guinea pig. :)

In fact, your iPhone use will probably be BETTER without the plane! Flight attendants are so touchy nowadays.

You could use Skype and a WiFi connection, but other than that, no.

Just to make sure everyone knows what im talking about, I have my normal phone and would like the use the iphone device as just another phone. Anything like that out there? Jailbreak or something?

@MuffinMonarch Yes… That is illegal, unfortunately, because of Apple’s contract with AT&T, unless you are an AT&T customer. There’s no way you can bring your iPhone to any other carrier and tell them to hook it up, they won’t do it. However, as I said before, the contract is up soon and you might be able to use it with another carrier at that point.

Jailbreaking does not allow you to use it on another carrier. You’ll need to look into unlocking the phone to use it on another carrier. You just won’t have some features like visual voicemail, etc.

@fireinthepriory Exactly what makes it illegal for me to use as I please a product that I purchased? Once the phone is mine I can do what I want with it. If I want to get a sim card from a different provider and use it in my phone, legally, I can do that. And as long as I can unlock the iPhone and make it accept another SIM card, no one can stop me. The Digital Millennium Copyright Act is very clear about protecting my rights to jailbreak, and unlock the phone that is owned by me.