It's unknown quite how they managed this, although we do know that certain spells do levitate things, such as the Levitation Charm, or Snape's self-penned spell, Levicorpus.
As JKR so enlightened us, all wizards have the power of flight innately but most require a broom to do so. If however, a wizard is able to channel that power himself then he will be able to fly unsupported. Voldemort invented this ability prior to the 7th book, something that astounds everyone who witnessed it.
In the Order of the Phoenix film, Death Eaters and Order members apparate and disapparate in clouds of black and white smoke respectively. In the film, both sides also appear to be able to "half-apparate" in which their bodies were made out of smoke, giving them the recently improvised ability to fly.
Sectumsempra is a curse invented by Professor Severus Snape, during his childhood, when he was known as "The Half-Blood Prince". He created it with the intention of using it against his enemies, and it soon became one of his specialties.
In Harry Potter and the Deathly Hallows Part II, when Snape is dueling Mcgonagall, he deflects her spell to take out the two Carrows before flying out the window and escaping.
Even though McGonagall is the Defence Against the Dark Arts teacher, she's unable to defeat the Potions master. It show's Snape's power. Yet not only does he refuse to fight back, he also seems to deliberately deflect one of McGonagall's spells into the path of two Death Eaters behind him.
Later in the year, McGonagall duelled with Death Eater Alecto Carrow during the Battle in the Astronomy Tower and later learned of Snape's murder of Dumbledore. McGonagall was initially appointed as Headmistress, but was demoted after Voldemort took control of the school and placed Snape as Headmaster.
Malfoy spots Harry and casts a Cruciatus curse; Harry, defending himself, using the Half-Blood Prince's Sectumsempra spell without knowing its effects. To his horror, it gashes Draco's face and chest, spilling his blood everywhere.
Harry became so enamoured with the spell that he eventually used it to finish off Lord Voldemort. Here's how Harry's relationship with Expelliarmus became his signature – and why that's a good and bad thing.
He is also revealed to be a double agent for Albus Dumbledore and the Order of the Phoenix. But many people forget that he also invented a number of spells. In the Harry Potter movies, Snape came up with the Sectumsempra curse when he was a student at Hogwarts, and it's known to cause painful lacerations on the target.
In Rowling's Harry Potter series, Dumbledore demonstrated the ability to possess wandless magic on several occasions, most memorably when he cast Aresto Momentum without a wand to save Harry from falling to his death during a Quidditch match. Lord Voldemort was also able to practice powerful wandless magic.
The Avada Kedavra – the killing curse from the Harry Potter Wizarding World is unforgivable, cannot be blocked, and is colored green.
Brooms are magical tools just like wands, meaning extremely powerful wizards, like Voldemort, can fly without them. This also means every wizard and witch has the ability to fly without a broom, it's just that most need brooms to channel that power.
Why does expelliarmus cause snape to fly into the bed in Prisoner of Azkaban film? expelliarmus is used to disarm an opponent. It's used over and over to cause the wand to fly out if peoples hands.
Severus Snape is one of the most divisive characters in the entire "Harry Potter" series. He was a double agent, so many character details were kept a secret. His mother was a witch and his father was a Muggle, leading to the moniker "The Half-Blood Prince."
It could only mean one thing – Snape was plotting to steal the Philosopher's Stone and use it to resurrect the Dark Lord! Once again, the trio had the wrong end of the broomstick. Snape was trying to prevent the Stone from falling into the wrong hands.
Alohomora, which is a spell that unlocks objects (and it's also Hermine Granger's signature spell).
Cruciatus Curse ('Crucio')
Harry tried to use this spell himself. The first time was against Bellatrix after she had killed Sirius. His attempt was unsuccessful because, as Bellatrix mockingly explained: 'You need to really want to cause pain – to enjoy it – righteous anger won't hurt me for long…'
Avada Kedavra
It's used to kill people, it's an Unforgivable Curse, and it was Voldemort's favourite, so it's going last.
I've always suspected Molly's lethal spell was a particularly well-placed and powerful stunner that stops Bellatrix's heart, which is consistent with the description of her death: Molly's curse soared beneath Bellatrix's outstretched arm and hit her squarely in the chest, directly over her heart.
Blood spurts from Draco's face and chest, and Myrtle beings screaming. Snape bursts into the room and heals Draco's wounds almost immediately. Snape hurries Draco to the hospital wing, commanding Harry to wait behind.
That same year, Aragog contracted an unknown illness over the summer, and despite Hagrid's attempts to heal and comfort Aragog by feeding him giant grubs, he eventually died on 20 April, 1997.
Yes, Dumbledore did ask Snape to kill him so Draco wouldn't. Dumbledore did indeed ask Snape to kill him, so that Draco wouldn't either succeed and maim his own soul, or more likely fail and be killed by the Dark Lord for his almost inevitable failure. "All the same, try.
Professor McGonagall is a Death Eater
According to the theory, McGonagall's seeming disregard for Harry Potter's safety, her talent for transfiguration, and and her stoic nature all point to the fact that she was a Death Eater.
I've noticed several people asking this question online. The answer is: NO.