Can anyone tell me about these unreleased Lego sets?

[Perry]

While searching around on Brickset I found these four Lego sets:

Car = 4033

Aeroplane = 4034

Boat = 4035

Space Plane = 4036

Are these hoaxes or something?

They are marked in Brickset as "Designer Sets". Upon further investigation I found a Lego set called "4037 Helicopter".

If anyone knows about the source material let me know.

[JopieK]

This happens more often:

https://brickset.com/sets/tag-Unreleased