Monier Monier-Williams

 "a car or a chariot of the gods, any self-moving aerial car sometimes serving as a seat or throne, sometimes self-moving and carrying its occupant through the air; other descriptions make the Vimana more like a house or palace, and one kind is said to be seven stories high"

Katha Upanishad

The Self (atman) is the owner of the chariot;

the body (sarira) is the chariot;

intuitive discernment and awareness (buddhi) is the charioteer;

the thinking function (manas) is the bridle;

the sense forces (indriya) are the horses;

and the objects or spheres of sense perception (visaya) are the ranging ground. 

The individual in whom the Self, the sense forces and the mind are joined is called the eater or enjoyer (bhoktar).

Right:  Return of Rama in Pushpak Viman Hindu Print Kalyan

For one who is devoid of real insight and has not properly and constantly yoked and tamed his mind – that is to say, for one who has not disciplined and controlled both his conscious mental faculty (manas) and the intuitive awareness (buddhi) which is a manifestation of the irrational unconscious – the sense forces become unmanageable, like the wicked horses of a charioteer.  But for him who is always full of intuitive awareness and who has tamed and yoked his mind, the senses are subdued like the good horses of a charioteer.

He who lacks the proper intuitive awareness and is thoughtless and impure, does not reach That Place [the state of transcendental existence] he tips over into the whirlpool of death and rebirth (samsara). 

But he who is full of intuitive awareness, thoughtful and pure at all times, reaches that place, whence one is not reborn.  The man who has for his charioteer intuitive awareness, and for his bridle the mind, attains the end of his journey – which is a great distance away.  That goal is the supreme abode of Visnu – the cosmic all pervading Self divine.

Then we have this description from the Ramayana, the pushpaka ("flowery") vimana of Ravana is described as follows:

"The Pushpaka Vimana that resembles the Sun and belongs to my brother was brought by the powerful Ravana; that aerial and excellent Vimana going everywhere at will ... that chariot resembling a bright cloud in the sky ... and the King [Rama] got in, and the excellent chariot at the command of the Raghira, rose up into the higher atmosphere.'"

Wonders In The Sky - Unexplained Aerial Objects From Antiquity To Modern Times - and Their Impact on Human Culture, History, and Beliefs - Jacques Vallee and Chris Aubeck

Circa 4780 BC: The fiery Vimanas of King Citraketu

The earliest dated story we are able to find about flying devices of non-human origin comes from the ancient literature of India. For instance the Bhagavata Purana, also known as Srimad Bhagavatam, a text that is part of Hindu literature [sic], states that while Indian King Citraketu was traveling in outer space on a "brilliantly effulgent ship given to him by Lord Vishnu," he saw Lord Shiva: "The arrows released by Lord Shiva appeared like fiery beams emanating from the sun globe and covered the three residential ships, which could then no longer be seen." {Srimad Bhagavatam, Sixth Canto, Part 3). If the reference to this particular King is trustworthy, the event would have taken place about 4,780 BC.

The Vedic literature, including India's national epic, the Mahabharata, a poem of vast length and complexity, contains many descriptions of flying machines generally called Vimanas. Another text, the Ramayana, which can be loosely translated as 'the travels of Rama,' tells of two-storied celestial chariots with many windows that roar off into the sky until they appear like comets. Sanskrit books describe at length these chariots, "powered by winged lighting., .it was a ship that soared into the air, flying to both the solar and stellar regions."

There are no physical remains of ancient Indian aircraft technology but references to ancient flying machines are commonplace in the Indian texts. Several popular epics describe their use in warfare. Depending on one's point of view, either it contains some of the earliest known science fiction (a sort of Indian Star Wars) or it records conflict between beings with weapons as powerful and advanced as anything used today.

It is a curious fact that the yantras (Sanskrit for "machines") described in later Indian texts were less powerful than those mentioned in greater and older works. Does this imply a gradual departure from fantasy towards realism? Some have proposed the change reflects a loss of knowledge. Richard L. Thompson writes:
"Some ascribe this to the fantastic imagination of ancient writers or their modern redactors. But it could also be explained by a progressive loss of knowledge as ancient Indian civilization became weakened by corruption and was repeatedly overrun by foreign invaders. It has been argued that guns, cannons, and other firearms were known in ancient India and that the knowledge gradually declined and passed away toward the beginning of the Christian era."
(Alien Identities, San Diego: Govardhan Hill, 1993, 258.)