recalling dreams inside dreams or fals memory

I was dreaming of driving with a friend, than we got to a place with very very cool looking houses, when we got there I KNEW I was there before, it wasnt like i remembered it- i knew i was there like you'd know if you walk the street outside your house and say- i KNOW i was here before..
i even told my friend- i was here- look, there's a huge castle overthere- i turned and pointed at a mountain- and the castle was there, just like i remembered..
that i remembered when i was there last- it was when i had a van with wings and i drove it over (flying) this place and landing there..
i knew i had this van 100%, it wasnt the foggy dream fals memory that you dont really know y u do things, it was me (i didnt know i was dreaming, but i thought i was awake and had my own personality)
so in the end- when i woke up- i got that i dont own a flying van (damn shame) but still i had the memory of the first time i was in the dream place and flying in the van, memory that i got from the dream i just had. and i was trying to figure out if what i recalled was really a dream i had in the past, forgot it and i remembered it inside the dream tonight or the dream gave me a SUPER SUPER fals memory- to the point i dont know if it happend sometime or not..
what do you think?

it's called deja vu.
it's hwen your brain doesn't recognise a message was sent so it does it a second time slightly altered from the first one giving you the sensation something has been done before

Alternatively complex self-deception by the subconscious in dream.

I've had a similar experience to this, of remembering a dreamscape while in another dream. I dreamt I was at the beach in my hometown, but instead of its regular layout, there was a large , narrow cliff that sort of wrapped around this massive, 100-ft tall spire. The spire was coming out over the beach below, so that the cliff wrapped around it (but always about 30ft away from touching the spire) about halfway up. The spire was very narrow, maybe 5ft and tappered ever so slightly. It looked like it was made of bone and was scorched near the top. A few weeks later, I had a dream of driving down the main drag with my grandmother, and as we passed the road down to the beach, I looked out the driver's side window and could see the bone spire in the distance with its wrap-around cliff. I immediately knew what it was and what that portion of the landscape looked like and recalled being there before. In retrospect, I kick myself in the ass for not recoginizing I was dreaming due to this recalled dreamscape.

I'd say it's possible you may have dreamed the castle-mountain and flying van before and just forgot it (either that same night, or earlier). I think once dreams start to become more and more part of your long-term memory, the chances of associations triggering dream-memories increases.