Can't help you with the plane, although I'm sure it was just made up, but I can tell you that the Submarine is the Das Boot sub. They were filming in the same place and borrowed it for a few shots. Also, they managed to do some damage to it and it later broke up!

My dads into the weird and wonderful German aircraft from WWII and he dosn't recognise it, though he says it kinda looks like a prop version of a jet that never quite made it.

Looks like a cross between an Me329 and 265 to me.
I didn't think this aircraft actually existed in real life, so they based it around a couple of different models that did and threw together something that looked good. If you read this, it appears I was right... http://www.indygear.com/props/planes.shtml (at the bottom of the page)

Ozzy 8)

It couldn't possibly have existed at the time the movie is set.
At the beginning of the movie when Indiana is in the South American jungle, the time indicated is 1936.

There would no have been such a plane at this time. In fact, I think the Submarine is a bit 'optimistic' too.
Someone may be able to tell me but I don't think there were any (or at least very many) German Subs in 1936.
Let alone, secret Sub bases near Madagaska.

Oh yeah, just a bit of trivia. I love that Movie, I have seen it 'Hundreds' of times. But there's just one thing I can't come to terms with:

Indy swims from the 'freighter' to the Sub, and is on the deck, outside the Sub. A map of the Indian Ocean is then shown with little dots representing the course the Sub takes to it's secret base. (I'm pretty sure down to the bottom of Africa, near Madagaska)
Anyw it's many hundred miles and I'm certain that they would not have been on the surface the whole way, especially to a 'secret base'. Why doesn't he drown?

That is a great site!  Where on Earth do you find these things?  I especially love the part about the float-plane.  THe guy flies it to work and back every day!

Isn't there meant to be an Iniana Jones IV being made?

If there is an Indiana IV, it will have to have Harrison in it.
Just wouldn't be the same. Like the Beatles without Lennon, McCartney, Harrison (goodness me a pun....kinda) and Starr.

Have you heard if he would do it? If not him, who do you think might be able to carry the baton.

If I had to 'put up' with soemone else younger, I'd have to choose maybe Matt Daemon or...............oh yeah, I know, probably Brad Pitt.
But they'll probably try some 'flavour of the month' Aussie.
Kind of 'Goerge Lazenby all over again................lol

I crack me up! 

(See, I've even got an award that says so!  )