Hope I made you proud. Bumi is Avatar Aang and Katara's first child and eldest son, as well as the only one to be born a nonbender among the couple's three children; he later developed airbending abilities after the Harmonic Convergence of 171 AG.

Why didn't Bumi get Airbending?

Why? Airbenders were highly spiritual, and as a result, all of them were benders to some degree or other. The Air Nation was all-bender, and so, the Fire Nation needed the power of Sozin's Comet to wipe them out. Thus, it's baffling that Bumi, as the son of an airbender, is a nonbender.

Is Bumi a powerful airbender?

King Bumi was chosen as the Avatar's opponent, but it was soon realized that the young airbender had made a mistake as Bumi threw off his royal robes and flexed his muscles, revealing himself to be a powerful and muscular earthbender.