Thor does not need to fly.
Odin (Brahma), Loki (Shiva) and Thor (Vishnu)
Thor's strength is so great it threatens the universe itself:
It seems obvious that Útgarða-Loki's giants were terrified for the same reason that Hymir was: Þórr's strength is great enough to threaten the very structures which hold the universe together.
Thor creates a star out of a toe by throwing it into the sky:
A toe was sticking out, so Thor broke it off and threw it up into the sky to make the star Aurvandilstá ("Aurvandil's Toe").
Basically the hammers 'fulfills the wishes of Thor'
When Thor receives his hammer, Mjölnir, it is revealed that he can smite anything as hard as he so desires, and the hammer will not fail him. Thor can throw Mjölnir at anything, and it would strike without fail, never missing and never flying so far that it cannot return:
Then he gave the hammer to Thor, and said that Thor might smite as hard as he desired, whatsoever might be before him, and the hammer would not fail; and if he threw it at anything, it would never miss, and never fly so far as not to return to his hand; and if be desired, he might keep it in his sark, it was so small; but indeed it was a flaw in the hammer that the fore-haft was somewhat short.
Thor revives his two goats Tanngrisnir and Tanngnjóstr after slaughtering them for a meal:
Thor tarried there overnight; and in the interval before day he rose up and clothed himself, took the hammer Mjöllnir, swung it up, and hallowed the goat-hides; straightway the he-goats rose up, and then one of them was lame in a hind leg. Thor discovered this, and declared that the husbandman or his household could not have dealt wisely with the bones of the goat: be knew that the thighbone was broken.
Source: The Prose Edda: Gylfaginning