how about joyrides?
 

Very useful information on US visa requirements and a great help.

Just one question: what if I just want to do a joyride/dual flight with a CFI at a club/school? do i still need to apply for a FAA conversion on my lic. or can i just turn up at the airport with my tourist visa?

I did exactly this a short while back and wasn't asked for any documentation.

I don't want to get anyone in trouble, but I did a touch and go at a major international airport and some moderately low level turns over a historic city centre.

I have never been asked to see my documents other than when I applied in person for a FAA PPL based on my UK one. Even post 9/11 no one seemed interested when flying with an Instructor.
I even managed to hire a PA28 without a checkride, just took one of the guys who worked in the hangar with me, again no one asked to see documents. I must have an honest face, or he was looking for the insurance money, that was post 9/11 too. It is a treat to be able to touch and go at International airports without having to stop to pay huge sums of money. Wish we could fly like that here. :O

Does anyone have a reference to a document that states
what kinds of flights require a visa?

I ask as I'm in the US frequently on business, and enter on the
Visa-Waiver scheme. I recently phoned a school to see about
a dual flight just to sightsee and try to maintain some semblence
of currency, but was told that ALL dual flights require a visa.

That didn't ring true, as I thought that people who were
doing a rental check-out or BFR didn't need a special visa,
but of course I don't have a reference to the "official" document...

If you look here, there is a TSA letter that is relatively recent (Oct.19, 2004).

The letter confirms TSA's position that "flight training" means "only training that a candidate could use toward a new airman certificate or rating". Accordingly, the new "Alien Flight Training/Citizenship Validation Rule" doesn't apply to rental check-outs, conversion training on light aircraft (i.e., training that does not lead to an official type rating), or BFRs.

Thanks very much MLS-12D!

Finally a definitive answer! thanks alot MLS-12D

You're most welcome.

Good luck with your flying.