I've seen like 'optical illusions' and such that gives the subject of a particular photo the illusion it is suspended in air or floating. My mother wants to dress up for Halloween and take some pictures for her friends as a kind of greeting card, and she wants to have the appearance she is flowing.

 

we usually lift our challengers with a block and tackle, this gives the effect of floating but you have to be creative when you take the photo otherwise you run the risk of getting your cables and chains in the shot
and if its a windy day that sucker can really begin to sway.

 

Find a road with small hills.....launch yourself at a high rate of speed and you will get the effect of floating after passing the crest of the hill........the effect will only last a short time and the landing may be a bit rough....but again, it will give you that floating effect....
The larger the hill the longer the floating effect, but the harder the landing.........
(hope that helps....... )

 

Yes those are called stereograms. They have been around for about 20 years. There is even software that can create those images.

Here are a few. If you let your eyes go out of focus while you look at the center the 3D image will appear. One has the Status of Liberty in it.