Many reports claim Earth has been visited by intelligent extraterrestrials, but no solid evidence has come forth. It appears that some of the people that dwell on this planet are either nuts or something very strange is going on.
If earth is being used as a type of intergalactic documentary by extraterrestrials, one can imagine that a type of Star Trek Prime Directive is in place. So technological ideas should be thought up by Homo sapiens and not given by some alien race.

 
 
 
 
 
 
 

Some conspiracy theories state that current advances in technology are due to extraterrestrial involvement, either by...
1 Aliens give secret government agencies highly advance technology.
2 UFO crashes are salvaged and studied by military scientists.

I have read many alien/UFO reports and found many similarities with ideas of molecular nanotechnology.
Here are a few that I have encountered.

1 Aliens are seen often with one piece suits, appearing like diving suits. Bio space suits with millions of molecular machines. The suit is in essence an exoskeleton, as envisioned by Eric Drexler.
Engines of Creation chapter 6 under Space and Adavanced Technology

2 UFOs are described structures with no bolts, no rivets, very light and very strong materials etc (structures not built but grown). A carbon material is probably used.
Engines of Creation chapter 4 under Molecules and Skyscrapers

3 Fog or mist associated with UFOs with the ability to move objects. An idea called Utility Fog (by Dr.J.Storrs Hall) came to him while driving to work and thought of a way to replace seat belts. This idea has now expanded in many ways.
Utility Fog

4 The claim of aliens long life or near immortality, a possible type of nanomedicine or cell repair machines.
Engines of Creation chapter 7 under Cell Repair Machines, Nanomedicine

5 'Walking through walls' nanomachines infecting a surface so when in contact nanomachines unlock the molecular structure of the surface then lock structure back again after the desired object has passed through.

6 Instant communication from across the universe (faster than light), something I have not heard from alien/ufo reports or ideas of nanotechnology but still interesting. The ghostly method of Quantum Particle Entanglement.
Communication by Entangled Particles

Is alien technology really universal technology?

article by nm