Already baby Unicorn proved to be able to levitate herself with high speed as well as pass walls and break chains just to screw PinkiePie up, I think Twilight do not levitate herself only because she does not want to show off or because many writers in my little pony did not watched pass episodes, so they have no idea that Twilight is a power house what can teleport, lift 50 tons and know like hundreds of spells.



Seriously, in one episode she teleport all over the place and take Apples from hundreds of threes at once, and in episode with Apple Cinder, she is hardly levitating barrels, when she could do job of 4 ponies ( levitate apples, job of Applejacn and Fluttershy, and gather them, PinkiePie and Applebloom job ), yea, Twilight would do job of 4 ponies so they would focus on quality control and barrel moving.



In episode with Pinkie Keen, Twilight could not escape a Hydra, because autor of the story forgot that she can just teleport, and in episode with Magic Duel Twilight get tired easy and say that age spell is only for highest level Unicorns, should not she be stronger and the most powerful Unicorn in Equestria already ?



Yea, Twilight will use levitation and all kind of cool spells, if writers of the stories in MLP show will decide to spend some time to watch other episodes to learn more about main character, because she is powerful in one episode and in other is weak or not use magic at all.