Once Iroh and his fleet reached the shores of Republic City, they were quickly overwhelmed by a series of naval mines and the new high-speed aircraft fielded by the Equalists. At one point, Iroh himself was on the helm of his ship, launching fireblasts at the enemy biplanes; he managed to destroy several until he struck a bomb in midair with his firebending. The resulting explosion catapulted the General overboard and into the ocean, where he was later rescued by Avatar Korra.
With his fleet destroyed, Iroh and Team Avatar hid in the sewers of Republic City where they planned to take out an Equalist airfield. To prevent the second fleet from being destroyed as well, Iroh sent a message to Commander Bumi, telling him to wait with his fleet at Red Sand Island until the airfield was taken out. Korra decided to stay in Republic City to face Amon, although Iroh did not approve of the idea. Korra insisted and Mako decided to stay with her. The General allowed her to stay, stating that his grandfather would have trusted the Avatar's instinct and he should as well.
When Iroh, Asami, and Bolin reached the airfield, they were rendered unconscious by the electric fence that surrounded the complex. They were caught and subsequently imprisoned, where the group was confronted by Hiroshi Sato, who told them that he had intercepted General Iroh's wire to Bumi and that he knew exactly where his fleet was hiding. Seeking a means of escaping, the General asked Bolin if he was a metalbender, to which he received a negative answer. Naga, however, arrived on the scene shortly afterward and broke the three out of their cell, allowing them to head toward the airstrips.
After escaping, Iroh pursued a taxiing biplane down a runway. By utilizing his firebending in a manner similar to rocket propulsion, he successfully boarded the plane as it took off, hijacked it, and forced the pilot to bail out.
Once inside, Iroh struggled to control the machine; eventually, however, the general gained control of the aircraft and used it to intercept the squadron of five aircraft flying over Republic City. He was able to destroy two airplanes during his initial attack with lightning. Following this, his own biplane was destroyed when an Equalist bola jammed the propellers.
Utilizing the rocket propulsion technique a second time, Iroh boarded a second plane, fatally damaging another plane with his firebending before commandeering the biplane. During the fight, Iroh's biplane was damaged by the last aircraft which had dropped a bomb on the tail of his aircraft. As the other biplane prepared to continue the bombing, Iroh used his firebending to detonate the remaining bombs in the attacking plane's bomb bay.
Despite his success, Iroh's airplane was damaged to the extent that it could no longer remain airborne. He unsuccessfully attempted to steer the plane away from Aang Memorial Island and had to bail out, grabbing onto the Equalist banner hanging from the statue of Aang to save himself. Iroh watched as his biplane crashed into the statue's face, causing the giant replica of Amon's mask to fall off into the water. Iroh then thanked Aang for watching over him.
Iroh is a disciplined and determined young man. Like his namesake, he is very cautious and methodical in his approach during battle. Furthermore, he has shown great bravery on the field, willing to risk his life to aid his allies without hesitation. Despite his senior rank among the United Forces and his status as a member of the Fire Nation Royal Family, Iroh is a humble man, openly showing his sincere gratitude for other people's assistance.
As a member of the Fire Nation Royal Family, Iroh has demonstrated great skill in firebending, as shown by his ability to generate lightning and the use of firebending to propel himself through the air with great speed and accuracy, fast enough to catch up with a speeding airplane. He also effectively took down numerous airborne planes with only his bending. Furthermore, he is a quick learner, as he was able to figure out how to pilot an Equalist biplane despite his lack of experience with them.
Iroh is the fourth person to be seen using firebending to propel himself into the air, and the second to have done so without the aid of Sozin's Comet. He is also the first person to do so in The Legend of Korra.
Having destroyed many aircraft, Iroh would be considered a flying ace, that is, a pilot that shoots down five or more enemy aircraft. He also earned it in a day without any prior experience or training, an incredible feat for a real world pilot. That being said, he would be the first known flying ace in the World of Avatar.
After the initial skirmish following his arrival in Republic City, General Iroh gained a burn scar on his left arm reminiscent of his grandfather Zuko's burn scar.
The way that Iroh said that if "[his] grandfather would respect the Avatar's instinct, [he should, too]" is very similar to how Zuko would ask himself what his uncle would do.
The original Iroh and KingBumi worked together in the Order of the White Lotus, much like how Zuko's grandson Iroh and Aang's son Bumi now work together in the United Forces.