If there is something that the Dragon Ball series prides itself, it would be their contribution to the anime world. DB franchise is one of the pioneers of aerial battles in fighting anime. The use of weapons is also Goku’s main power-source when he was just a little monkey boy. Overall, Dragon Ball’s asset was its great fights that involve fighters exchanging blows in the air.
But why is flying not allowed in the Tournament of Power? Is there any valid reason to negate flight during the tournament? If flight is allowed, things would be very different than now. You would see more people dropping out or the other way around. Fast-paced action will also be possible with the use of flight. And more than that, techniques would be cooler than they are right now.
This also applies to the use of weapons. Majority of the fighters from Universe 7 are hand to hand combat experts. Even Goku, who used to take fondness of his magical stick reversed to hand to hand fighting later on in his life. But other universes might be different than right now if the use of weapon is allowed. Imagine Universe 3 warriors with plasma-photon-name-that-sounds-like-high-science weapons attached in their bodies.
There might be a reason why the Grand Priest decided that flight and weapons should be prohibited in the Tournament of Power. And that reason is very simple: the two Zeno-chans cannot keep up with fast-paced and high-level battles. Zeno is not a fighter, and he is just like another five year old kid who enjoys all the big and destructive explosions. You wouldn’t even be sure if he can comprehend Beerus VS Goku.
This reason was revealed in the latest chapter of the Dragon Ball Super manga. The Gods of Destruction has shown an exhibition match for the future Zeno-chan so that he will know what a Tournament is like. But because Gods of Destruction are high-level fighters, they move faster and more complicated than the two Zenos could comprehend.
Because of this, the Grand Priest suggested to cancel the tournament. Goku overhears this and tried to convince the Zeno-chans that battle against mortals would be different and easier to comprehend. And because of this, the Grand Priest suggested that Goku and Toppo would fight with no flight allowed.
The two Zenos enjoyed Goku and Toppo’s battle and thus, the Tournament of Power will still run. But for the Zenos to enjoy watching, flight will not be allowed. Thus, Tournament of Power in the anime does not allowed flight.