Ancient Vimana, as described in the ancient Sanskrit Tex.

The Sanskrit word for space craft of aircraft is Vimana. In India you can find the picture of Vimanas in temple curving in many places. 

The Ellora caves are located near the city of Aurangabad. In addition to curving of Vimana there are some other interesting things there. Basically what you have at Ellora is a huge mountain made of stone and temple curved of solid stone in this place. 

According to the ancient text Bhagavata Purana :

Dhruva lived during a period of time called the Svyambhuva Manvanta. Here we have understand something about the vedic concept of time. The basic unit of the vedic cyclical time concept is Kalpa or Day of Brahma. It lasts for 4 billion 320 million years is followed by a night of Brahma which also lasts for 4 billion 320 millios years. 

Different kinds of Vimana : 

1. Spiritual 
2. Subtle Materials
3. Gross Materials 

The Vimana of Dhruva was spiritual Vimana. 

2. "The sage Kardama exercised his yogic power and instantly produced a Vimana that could travel at his will" - Bhagavata Purana 3.23.12

Kardama Muni was a great mystic yogi according to Bhagavata Purana. 

"In the Vimana were lives swans and pigeons, as well as artificial swans and pigeons so life like that the real swans, vibrating sounds,  flew up-to them, thinking them live birds like themselves" - Bhagavata Purana 3.23.20

"Kardama traveled in the Vimana through the planets,  moving like the wind.  His Vimana, which could fly at his will, surpassed the Viamans of the demigods" - Bhagavata Purana 3.23.41

3. King Shalva was a demonied king living on this planet.

"Maya Danava, who conquered his enemies cities, constructed a flying iron city named Saubha and presented it to Shalva" - Bhagavata Purana 10.76.7

Shalva used this Vimana to attack the cities on earth. The Vimana was made of metal, not spiritual or subtle metarials substance.

"This unassailable vehicle was filled with darkness and could go anywhere.  Upon obtaining it,  Shalva went to Dwaraka" - Bhagavata Purana 10.76.8

Dwaraka was the city of Krishna. 

"From the Vimana came down torrents of weapons" - Bhagavata Purana 10.76.10

Ashanayah = Thunderbolts (B. P. 10.76.11)

"A fierce whirlwind arose and blankets all directions with dust" - Bhagavata Purana 10.76.11

"Thus terribly tormented by the spaceship Saubha. Lord Krishna city had no peace,  O King,  just like the earth when it was attacked by the three aerial cities of the demons" Bhagavata Purana 10.76.12

According to Bhagavata Purana 7.10

Maya Danava gives demons three huge metal Vimanas, with power of invisibility. 

Demons use Vimanas to conquer various planetary systems.

Demigods ask Shiva for help. 

"The arrows released by Lord Shiva appeared like fiery beams emanating from the sun globe" - Bhagavata Purana 7.10.58

Weapons of the Shiva kill demons on the huge Vimanas.

Maya Danava restores life of demons by putting them into a reservoir of special liquid.

Demons resume battle.

Krishna give Shiva new more powerful weapons,  which Shiva uses to finally destroy the flying Vimanas of the Asuras.

" At a moment the Vimana built by Maya Danava appeared in many identical forms,  and the next moment it was again only one. Sometime it was visible, and sometime not.  Thus Shalva's opponent could never sure where it was" bhagavata Purana 10.76.21

"Shalva's spear made a frithening roaring sound on the battlefield" Bhagavata Purana 10.77.12

"Shalva hurtling spear lit up the whole sky like a mighty meteor, but Krishna tore the great weapon into hundreds of peice with his arrows." -Bhagavata Purana 10.77.13

"Krishna struck Shalva's Vimana with a torrent of arrows, appearing like the powerful rays of the sun" Bhagavata Purana"

Shalva comes out of the Vimana and personally attacks Krishna.

Krishna wounds Shalva. Shalva disappears mysteriously. A messenger appears saying 'your mother has sent me to tell you that Shalva's has captured your father. 

Shalva reappears with Krishna's father as his captive. Shalva cuts off the head of Krishna's father with a sword. 

"Taking the head with him,  Shalva entered his Vimana,  which was hovering in the sky" - Bhagavata Purana 10.77.27

"Krishna detected that this was an illusion engineered by Maya Danava and employed by Shalva" Bhagavata Purana 10.77.28

"Krishna could see neither the messenger nor the headless body of his father" - Bhagavata Purana 10.77.29

"Smashed to piece by Krishna's weapon the Vimana fell into the sea" - Bhagavata Purana 10.77.34

So,  according to Bhagavata Purana, there are different kinds of extra-terrestraial beings and different type of Vimanas.  Some of them are made of spiritual elements of pure consciousness. Some of them are made of subtle metarials and some of them are gross materials elements.