Of all the martial arts masters introduced over the course of the Dragon Ball franchise, the wisest and first major one seen is Master Roshi. The creator of the Kamehameha Wave and capable of the deceptively powerful Evil Containment Wave, Roshi was able to stand toe-to-toe with the mightiest fighters in the original Dragon Ball. He then reminded everyone just how combat-savvy and formidable he remains in the sequel series Dragon Ball Super, with an impressive showing during the Tournament of Power.
However, while Roshi can still mix it up with the best warriors the Dragon Ball franchise has to offer, the venerable Turtle Hermit has never learned the ability to fly. Why is this?
The technique for Dragon Ball characters to fly was introduced approximately halfway through the original series, with Tien and Chiaotzu first demonstrating the ability against Goku and his friends while Goku initially relied on the Flying Nimbus to navigate great distances. By the end of Dragon Ball, he and Krillin would also gain the ability to fly as they reached adulthood, with virtually all of the Z Fighters throughout Dragon Ball Z similarly learning how as well. This included Hercule's daughter and Gohan's eventual wife Videl, who learned how to fly over the course of six months of training during the Great Saiyaman Saga. However, even by the Tournament of Power at the end of Dragon Ball Super, Roshi still has not demonstrated that he can fly, even as he faces off against formidable opponents from across the Dragon Ball Multiverse.
The cause of Roshi being unable to fly likely isn't due to the martial arts master being physically incapable of performing the technique, but one linked to a longstanding grudge that Roshi has held for much of his life. One of Roshi's old friends, Master Shen, had since become a bitter enemy; the two had an acrimonious falling out after their mentor, Master Mutaito, heroically sacrificed his life to imprison the evil Demon King Piccolo centuries before Dragon Ball's main story. While Roshi founded the Turtle School of Martial Arts, Shen went on to form his own rival program, the Crane School of Martial Arts, earning the nickname the Crane Hermit in the process for his fighting style's aerial techniques.
In addition to the Dodon Ray and Tri-Beam Attack, the Crane School also popularized the ability to fly as part of its fighting style, with Tien and Chiaotzu presumably learning the technique from Shen while training under his cruel tutelage. Given the heated level of animosity between Roshi and Shen, Roshi's decision to learn not to fly is likely heavily informed by the Turtle Hermit firmly refusing to learn any technique associated with the Crane School. No matter how beneficial it may have proven for him, Roshi was content on letting his students learn the technique for themselves and sticking to conventional means of transportation.
With no love clearly lost between the Turtle and Crane Hermits, spite is one hell of a motivator for Roshi not to learn how to fly, even as opponents and enemies in the Dragon Ball franchise become stronger and stronger. And yet, Roshi has also proved he doesn't particularly need to learn how to fly in order to stay relevant -- especially given the sheer amount of expertise he continues to surprise the Z Fighters with. And as high-stakes as Dragon Ball can get, Roshi has always been one to prefer keeping his feet firmly planted to the ground.
