The Flying Motorcycle

Quote	Source
A low rumbling sound had broken the silence around them. It grew steadily louder as they looked up and down the street for some sign of a headlight; it swelled to a roar as they both looked up at the sky - and a huge motorcycle fell out of the air and landed on the road in front of them. ... "Hagrid," said Dumbledore, sounding relieved. "At last. And where did you get that motorcycle?" "Borrowed it, Professor Dumbledore, sir," said the giant, climbing carefully off the motorcycle as he spoke. "Young Sirius Black lent it to me." ... "Yeah," said Hagrid in a very muffled voice, "I'll be takin' Sirius his bike back. G'night, Professor McGonagall - Professor Dumbledore, sir." Wiping his streaming eyes on his jacket sleee, Hagrid swung himself onto the motorcycle and kicked the engine into life; with a roar it rose into the air and off into the night.	Book 1, Pages 14, 16 Sorcerer's Stone, Chapter 1, "The Boy Who Lived"
"an' Sirius Black turns up on that flyin' motorbike he used ter ride. ...Black argued, but in the end he gave in. Told me ter take his motorbike ter get Harry there. 'I won't need it anymore,' he says. "I shoulda known there was somethin' fishy goin' on then. He loved that motorbike, what was he givin' it ter me for? Why wouldn' he need it anymore? Fact was, it was too easy ter trace."	Book 3, Pages 206-207 Prisoner of Azkaban, Chapter 10, "The Marauder's Map"
He rolled onto his back and tried to remember the dream he had been having. It had been a good one. There had been a flying motorcycle in it. He had a funny feeling he'd had the same dream before.	Book 1, Page 19 Sorcerer's Stone, Chapter 2, "The Vanishing Glass"
"Here," said Kingsley brusquely to Mr. Weasley, shoving a sheaf of parchment into his hand, "I need as much information as possible on flying Muggle vehicles sighted in the last twelve months. We've received information that Black might still be using his old motorcycle." Kingsley tipped Harry an enormous wink...	Book 5, Page 132 Order of the Phoenix, Chapter 7, "The Ministry of Magic"

Pictures:
On the Harry Potter and the Sorcerer's Stone (Two-Disc Special Edition) (Harry Potter 1) DVD there is a Photo Gallery (via "The Library") where I found this artist's concept drawing of Sirius's Flying Motorcycle sitting beside Hagrid's hut. This artist, however, may not have known anything more than any of us. The films are not generally considered canon. (An excellent discussion of canon can be found on HP-Lexicon's Overview of Sources.)

Links:

That Mysterious Flying Motorcycle - An original editorial by Alyschera on mugglenet.

HP Lexicon's Table of Edits to Harry Potter and the Sorcerer's Stone which includes the change from "I'll be takin' Sirius his bike back." to "I best get this bike away." This poster had a good rationale for the change on the mugglenet forums. (i.e. Dumbledore, who testified that Sirius was the Potter's secret-keeper, would have not let Hagrid just ride off to give the bike back to the apparent traitor.)

Quotes:
JK Rowling's World Book Day Chat, March 4, 2004

Rita: Whatever happend to Sirius' flying motorbike?
JK Rowling replies -> Ah, good question. You'll find out, but the real sleuths among you might be able to guess.

Source: Accio-Quote