Enligt J K Rowling kunde människor flyga utan kvast, det är bara extremt svårt och riskabelt. (mer än Wandless magi)
JK Rowling. Yes, nearly all wizards use wands, which makes magic easier to channel. Wandless magic is sophisticated and takes more talent.
Q. So would that work the same for brooms? Would more advanced wizards/witches not need a broom to fly?
JK Rowling. Exactly. Wands and brooms (and flying cars) are tools that channel magic. The most gifted can dispense with them.
Q. Are there many wizards/witches at Hogwarts who can do magic and fly without wands or brooms?
JK Rowling. No, there's a cultural tradition of using wands and broomless flight is (as you might imagine) very risky!
(Source)
Vi kunde tolka Kennilworthy Whisps "Ingen stavning men devised gör det möjligt för trollkarlar att flyga utan hjälp i mänsklig form" som hänvisar uteslutande till stava och inte till stumfri magi.