Ancient texts from India mention flying aircraft and manuals exist that explain in detail the construction of such aircraft. The texts are in Sanskrit and people who have read it find similarities to such texts across other cultures.
If alternate history is to be believed, then the credit for the first modern aircraft should be given to B.G Talpul, who flew the first man-made flying machine in 1895. The Vimanas of yore had up to 300 pivots, 12 pillars, and 60 instruments.
The Sanskrit text, Samarangana Sutradhara, mentions quite clearly the attributes of a Vimana - "Strong and durable must the body of the Vimana be made, like a great flying bird of light material. Inside one must put the mercury engine with its iron heating apparatus underneath. By means of the power latent in the mercury which sets the driving whirlwind in motion, a man sitting inside may travel a great distance in the sky.
The movements of the Vimana are such that it can vertically ascend, vertically descend, move slanting forwards and backwards. With the help of the machines human beings can fly in the air and heavenly beings can come down to earth."
One of the greatest sages of ancient India, the Rishi Bharadwaj, who is revered as one of the seven prime Rishis of yore, wrote a detailed treatise on aviation. It is a treasure trove of information on how the ancients from Bharat or India developed different types of aircraft.
These ancients from Bharat used these aircraft for travelling from one place to another, for battles, and also for interstellar travel. The Maharishi’s treatise explains how an aircraft consists of 31 parts; it lays down the rules for creating a machine that does not catch fire, can hover motionlessly, become invisible to the enemy, and also the use of materials that cannot be cut by enemy weapons.
It explains how to knock enemy aircraft personnel unconscious, how to eavesdrop on conversation in enemy craft and how to find out the route that the enemy craft is taking.
One of the finest modern books that try to uncover the mysteries of ancient air travel is “Chariots of the Gods”, by Erich von Daniken.
Perhaps, not surprisingly, many of these Vimanas were saucer-shaped and could move faster than the speed of sound. Mercury was used as fuel to power these Vimanas. These Vimanas And these Vimanas were kept in hangars built for them, to be taken out at short notice.
The Vaimanika Shastra, a text written in the fourth century BC, mentions that these flying machines featured a dual drive system that allowed them to switch between a solar-powered drive and an anti-gravity energy source. These Vimanas often had more than two engines and could be fitted with missiles.
One text, the Ghatotrachabadma, mentions the existence of a huge Vimana, hovering 400 yojans in the sky. The Vimana was made of iron and propelled by engines shaped like elephants. One yojan is equal to eight miles, so we are talking about a flying object 3200 miles in the air.