The third of my three comments in Sulekha blogs on references to ancient flying using Vimana

Comment #3 (on 28th Oct. 2019 in Sulekha blog "Just for Subhash and Suresh Rao on the Vimaanas..." by Ushasuryamani: http://creative.sulekha.com/just-for-subhash-and-suresh-rao-on-the-vimaanas_637692_blog):

There are many claims on flying in ancient India (as flying planes etc.) according to this blog, but that might not be the reality .

Just because flying or flying cart / ratha is mentioned in a few poetic verses of ancient Indian / Hindu texts, that's not a clear evidence of flying or flying aircraft long ago, because flying in this case could idiomatically or poetically mean as moving rapidly or fast (as a fast moving / running cart or chariot etc.).

Even a 500 pages long book these days on aeronautics or astronautics, with equations and drawings all over, barely introduces us to the subject of actual flying currently. Can we thus take a few verses in old texts which just use the words flying and flying machine ('vimana') as a clear evidence of actual flying long ago? The answer in my opinion is 'No', and I am talking this from the point of an engineer who had the opportunity to learn the subject of flying in air and space and even work professionally solving problems related to aircraft and spacecraft.

Flying is not simple and it's quite difficult to build flying machines that actually work. It's quite different from moving on ground and in water by using carts, chariots and boats (which could have been called vimana long ago). Moreover, taking off or landing a flying machine (aircraft or spacecraft) safely is quite complex, risky and difficult, as also seen in the recent loss of ISRO's lunar module during landing in spite of numerous highly educated and trained people working on the project and using lot of resources.

So, my feeling is that we should not rely on a few verses in ancient texts, alluding to flying (which could in reality simply imply moving or running fast) or using the word 'vimana' (perhaps a cart or chariot, and not aircraft), as real evidence of flying machines used by humans (Indians) thousands of years ago.

As for the write-up in the above "Ever since I read about the Marati wise gentleman Tarpade who developed the first airplane and flew it on the Shivaji Park area.. referring to the Vedas as his inspiration to use the Mercury technology I had been inquisitive to learn more. ...This aircraft is said to have flown for a while and brought back. The Maharaja of Baroda is supposed to have financed this venture. The British suppressed this info., I heard and the credit was given to the Wright Brothers for the first airplane.", that probably never happened and it is just a tall claim.

If someone in India had built an airplane before anyone else, which the British allegedly suppressed according to the above, the Brits would have immediately taken that person or his aircraft knowledge / technology to Britain and built world's first aircraft in Britain (based on Indian's knowledge and technical knowhow). But that did not happen. Brits not only did not build the first aircraft (flying machine), but they also were lagging behind others (Americans, French and Germans) considerably during the early years of aircraft technology and research, which certainly would not have been the case if they knew that someone in India had already built an aircraft and which they were able to suppress

'Pushpak Viman' in the Ramayana flew at a speed 400 miles / hr (FaceBook post, Item # 20, dated: July 25, 2020,   https://www.facebook.com/photo.php?fbid=1689905507841319&set=a.445545838943965&type=1&theater ):

My comment:

It took more than 20 days (the time between Dushehra or defeat of Ravana and Diwali) by 'pushpak viman' for Ram ji and others to reach Ayodhya from Lanka (a distance of about 2000 km) after defeating Ravana and freeing Seeta.

That indicates 'pushpak viman' did not fly in sky at a speed of 400 miles / hr (or about 660 km / hr) which would have made possible for the return of Ram ji and others to Ayodhya in just 4 or 5 hrs, or a day, and not more than 20 days (the time between killing of Ravana in Lanka or Dushehra and the time of Rama reaching Ayodhya or Diwali).

In reality 'pushpak viman' probably was a ground vehicle (chariot etc.) made from light material (wood etc.); the old Sanskrit used viman in the sense of carts and chariots that traveled fast and not necessarily flying.

A viman (chariot etc.) traveling on ground at a speed 10 to 15 km / hr and covering a distance of about 100 km during daytime each day was the right kind of transport for Ram ji and others to reach Ayodhya on Diwali (in 20 days), after leaving Lanka (2000 km away) upon defeating / killing Ravana on Dushehra (about 20 days earlier).