Are aeroplanes, great weapons, travelling to space etc. in puranas are just imagination?

Question: Your Holiness Swamiji, Apparently, Mankind looks like made lot of progress over the period of last 5000 years – starting with discovery of Fire, Cultivating Lands, Constructing good buildings, splitting Atom, travelling to Moon. This has become possible with the knowledge marshalled by Man. My doubt is even in our Puranas, Aeroplanes, great weapons, traveling to Planets and other celestial places are mentioned. Are they just imagination? Have we now advanced or we lost all the knowledge once Mankind did possess. Kindly enlighten me.

Answer: Many have done research on this subject and come to the conclusion that men at certain ages were more advanced in certain fields. However, the present progress is really remarkable. But, it is presumed that there are other beings in different planets who are more scientifically advanced.