You can also use the new Surface Deform modifier in blender 2.79.

https://docs.blender.org/manual/en/dev/modeling/modifiers/deform/surface_deform.html

it's pretty sweet!

You can also use the new Surface Deform modifier in blender 2.79.

https://docs.blender.org/manual/en/dev/modeling/modifiers/deform/surface_deform.html

1. Select one of the objects you want to follow the plane
2. Go to the modifiers panel and create a Surface Deform modifier
3. Set the surface it's following to the plane.

Now the object should be following the plane. To copy this modifier to the other objects:

1. Select the other objects
2. shift+select the cube that has the modifier on it
3. hit ctrl+l to bring up the "make links" menu
4. choose Modifiers - this will copy the modifier from the cube with the modifier to the other cubes

hope that helps!