Bio-Volcanic Nature:
Just like the Magma Turtles of Skull Island, Rodan seems to be a mineral-fauna that has evolved to survive in geothermal environments such as volcanoes, maybe even more so as the creature sleeps in them possibly spending more time in them than even the turtles. Most creatures even other monsters who do not have a Bio-Volcanic nature or projectile attacks would probably not put in the effort to walk into an active volcano and burn or kill themselves trying to attack Rodan. The creature's body is much like it's home, with smoke and burning hot embers rolling off of it, burning those who touch it and stinting their eyes as shown with the holes burned into Mothra's wings during her fight with him in Boston. Against an opponent forced to fight Rodan in melee combat, Rodan has an advantage as any touch, be it him hitting them or them hitting him, results in them being burned. Damned if you do, damned if you don't.
While Rodan probably uses molten rock and heat to refuel his body much in the same manner Godzilla uses radiation, Rodan's body is able to maintain his geothermal body temperature for extended periods of time outside of one, even in super sonic flights in King Ghidorah's storms or after his body had been completely submerged in the ocean. Because of his high body temperature, weaponized viruses and such would burn up in his body and have no effect, and many chemical weapons would burn up before they could take effect unless it was some kind of coolant to slow down his lava circuitry and cool him off. Living in an environment mostly devoid of oxygen and filled with choking, poisonous types of gases, Rodan probably doesn't need much oxygen to function or any at all. This, the partially mineral rock and/or high body temperature could be why the Oxygen Destroyer had no effect on him despite being near where it was detonated.
Geo-Thermal Armor & Spiked Armor Chest:
Like most incarnations of the character, Rodan has a spike armor on his chest. However this rodan is equipped with an addition armor on the rest of his body formed from centuries of magma cooling off on his body as he bathes and sleeps in active volcanoes. Should any of the armor break off he can bath in more magma to repair it.
Lava Blood:
Not only does Rodan's blood burn those who injury him, but it also would cool off quickly should his armor be broken, acting as a temporary armor repair and keeping the creature from bleeding out least he lose too much of his precious heat and cool off to death just long enough for him to fly back to a volcano to recover.
Super Sonic Flight, Hurricane Winds and Sonic Booms:
As always, Rodan is able to generate massive winds with his wings. The creature is also capable of flying at speeds as fast as or faster than the speed of sound. This mach speed flight combined with the creatures size result in his drag creating slipstreams or sonic booms rivaling atomic bombs and capable of leveling entire cities without touching them by just flying by. His high speed and maneuverability would put even the the Male MUTO to shame as Rodan would fly circles around it.
Agility & Maneuverability:
In both a shocking display of flight capability and intelligence not seen since Gamera's buzzsaw attack in 1999, Rodan showed off many tricks including spinning like a drill to knock out many fighter jets at once. While most of Rodan's battle with Mothra was off-screen, it wouldn't be unreasonable to assume he attempted to do some fancy tricks in his battle with her.
Volcanic Eruptions:
Only mentioned in the novel of the film, Rodan had the ability to cause volcanoes to erupt by just flying by them at high speeds, causing a chain reaction like a bomb by bombarding them with his shock waves. While this was used in King Ghidorah's goal to terraform the Earth to his liking, this ability would be very situational and mostly unpractical in combat for Rodan.
