Hi austere, welcome to the forums, especially this section
firstly, realize that these crafts are infact travelling thru time, no matter where they came from.
1- if they are aliens from other planets in other galaxy's, they've got to travel faster than light, meaning cut thru time in order to get here.
2- if they were in fact people from earth from the future, then they must be travelling backwards in time, seeing their advanced technology and dissapearing like you said. * read down by the quotes
but one thing to think about is that there has been little aliens found dead (and some alive) around UFO recovery sites, and let's not forget the countless abduction testimonies describing the alien figures clearly.
(an ex-top-secret-clearance scientist testified that the US gov't has over 57 classified species of extra terrestrial life documented)
this is why i dont think this UFO crafts are humans from our future, it just doesnt fit the current puzzle pieces, ya know? but i doesnt mean you are wrong. this area of discussion is still up in the air so we can't discount any speculations yet. in fact all theories and wild ideas can prove to be helpful.
i dont think humans will have the power to travel back in time, thats a power for higher dimensional beings only. we can, of course- rocket forward in time, this will be space exploration at its best. but who knows just like prometheus stole fire from the gods maybe we will someday achieve the godly status of time travellers.
And, not all of them, are constructed on this planet, in this time, or this dimension.
a good statement- because it has been rumored that the government has already began engineering devices and possibly crafts based on the UFOs technology that they have recovered. It has even been proven that they Got one of these Crafts to work, a human was able to navigate the craft up to speeds of Mach20!
(this supports Your idea actually- because think about this- what if the government has already sent someone into the future(space) inside one of this newly developed (or original) crafts - then it could definetely be true that this man could go into the future(space) and one day return (might be before he even left!) ) its really mind boggling. or maybe they havent left yet- but soon the govt will finish the engineering problems and finally send someone out- but we've already seen him visit?!
i agree with your idea- but i think theyre other life forms (beings, aliens, whatever) from the future that are coming here- not humans from our future on earth. think about this:
theres aliens from other galaxies, they are advanced enough to travel space with their gravity-propulsion crafts- they visit here and there and we've even seen them and some have crashed (they can break light speed but cant fly straight??) these are your little gray dudes.
theres interdimensional beings- these are the true time travellers, except we cannot really see them- these beings go in and out of dimensions, one of them being Time. these are your ghosts, angels, and that kind of thing-
these beings work on the other side of Time, trying to fix things of the past after seeing the future. but u see its an ongoing war i think. because of
free will the future is re-written many and many times over. this beings have a very busy job. since they are interdimensional this means they have no physical body to worry about- they can fly from one end of the universe to the other fairly easy (a speculation of mine) while travelling in time. they are like energy beings, or spiritual beings, if you will. this is what i believe is the next step up in life forms. (when you die)
of course it can't be taken as more than just a speculation, but i think it will spark some ideas in your heads too. i would go deeper but that would kind of steal the threads flow with my wild ramblings.