Certainly, not everyone can provide the correct answer to this query.
While initially not widely practiced, the ability to fly eventually became commonplace within the Dragon Ball series. By now, most individuals, including some ordinary humans, have attained this capability. However, there's a seemingly straightforward yet elusive question: When did Goku learn to fly?
Flight Capabilities in Dragon Ball

The notion of ordinary humans flying through the skies was introduced by characters like Tien, Chiaotzu, and the Crane School in the early stages of Dragon Ball. Initially, flight was simply hovering above the ground rather than full-fledged aerial maneuvering as seen today, yet it proved to be quite useful. With adept control over Ki, humans could achieve this feat.
As for Goku, he was able to fly by using his tail rotation when he was young, although this ability quickly vanished when his tail was removed. Subsequently, Goku utilized the Nimbus Cloud for aerial travel. However, the specifics of how Goku could fly using his own power remain unclear, prompting many to ponder how and why he accomplished this.
When and how did Goku learn to fly?

As a skilled warrior and master of his own strength and Ki, it's highly likely that Goku's flying ability was initiated during his battle with Tien. After witnessing the Crane School students employing this technique, Goku imitated it (similar to how he learned the Kamehameha wave).
At the end of the initial Dragon Ball series, Goku showcased his flying ability to combat Piccolo's son at the World Martial Arts Tournament. This occurred after his training with Kami for several years. By the time of Dragon Ball Z, Goku had fully mastered this power, likely executing it proficiently when Gohan was just born.
Besides Goku, his closest companions Krillin and Yamcha are also believed to have learned flight around this time. It seems that the training from the deities made it easier for Z warriors to harness their Ki, thus enabling them to fly and utilize other powers. As a result, flying later became a basic skill known to everyone in the Dragon Ball universe.
