Perhaps most directly, Mother Talzin is shown to be able to use the Force to levitate:
Another notable example of Force flight occurs in Lords of the Sith:
Using the Force, Vader stopped his rotation and reeled himself in
toward the large, jagged, smoking hole his interceptor had torn in the
transport’s hull. Loose hoses and electrical lines dangled from the
edges of the opening, leaking gases and shooting sparks into space. A
portion of his ship’s wing had survived the impact and was lodged in
the bulkhead. The rest had been vaporized on impact.
Lords of the Sith
Here Vader has ejected himself into space, and used the Force to propel himself through vacuum toward a ship. Of note is that while Vader seems to be achieving flight by mentally grabbing hold of the ship (suggesting that he’s using an object to "grab onto"), he’s nonetheless able to affect himself directly with the Force (stopping his rotation).
Some Force jumps, in canon, appear to be using the Force directly to enhance one’s trajectory (rather than to give one enhanced strength):
Then you are flying upward. Yes. Flying. You never knew you could. But
you can. You are. Freezing carbon gas is filling the pit, but you are
above it now, perched on a pipe attached to the ceiling.
So You Want to Be a Jedi?
As to why we don’t see this more frequently:
- Strength. Luke, Vader, and Talzin are all powerful, and the latter two are highly trained. It’s probably just harder to move oneself through the Force than to move external objects, particularly when it requires constant effort (like Talzin’s levitation) rather than a one-time exertion (perhaps Luke’s jump).
- Risks. Flying requires a constant exertion, as mentioned, and thus constant concentration. Eventually the Force user will grow tired (as we’ve seen, Force telekinesis definitely causes mental or physical exertion), and if they’re too high, they’ll fall. In combat, this could be a serious risk: do you really want to be absolutely dependent on your concentration, 1000 feet above the ground, when fifty battle droids are firing at you and you have to deflect their shots with your lightsaber?
But even outside combat, it might be impossible or imprudent for the average Jedi to fly for any extended period of time. We mostly see flight indirectly (through short, enhanced Force jumps), rather than as a prolonged thing. Much safer.
- Not much of a benefit. Ships and jetpacks are generally easy available and don’t require effort or risk. Why not just use them (as Jedi indeed do, at least in the case of ships).