"Everything that this aircraft is sending is almost instantaneously sent down to people who can process, exploit and disseminate that information within minutes to our leadership," Bartran told CNN, which was granted access to Osan Air Base.

High-altitude spy plane

First taking flight during the Cold War in the 1950s, the Dragon Lady was built to fly so high that it couldn't be detected by Soviet planes.

Newer models of the aircraft have been modernized with new sensors and cameras.

At $250 million a piece, the piloted spy planes are equipped to handle a variety of intelligence gathering tasks that newer unmanned aircraft like drones can't do alone. It makes the Dragon Lady a critical asset in detecting what the North Koreans are really up to.

"We provide what's called multi-in (intelligence). We're the only true multi-in in the theater," Bartran explained. "We can both see and hear things at the same time."

In the months since Donald Trump became US President, the rhetoric between North Korea and the US has intensified. Both sides have threatened the other with total annihilation.

But the unpredictability of both leaders could mean tensions could escalate -- and possibly boil over -- at any time.

The Dragon Lady's presence over the Korean Peninsula, Bartran explained, is to ensure the US has the information it needs to act or respond. The intelligence the jet sends back to Washington could mean the difference between peace and war.

"I can assure you that, in close collaboration with our allies, there are strong military consequences if the DPRK initiates hostilities," Mattis said.

Some of those "consequences" would likely originate from Osan Air Base. In addition to housing Dragon Lady spy planes, it's also the base for two squadrons of F-16 fighter jets -- whose pilots train with the motto to be "ready to fight tonight."

'Ferrari' of planes

A third F-16 squadron is stationed at Kunsan, the other US Air Force base in South Korea.

"This is Ferrari -- that is the best way to describe this thing," Maj. Daniel Trueblood, a F-16 pilot from the 36th Squadron said as he proudly showed off his fighter jet.

He boasted about the aircraft's supersonic speed -- saying it can move at 16 miles per minute.

That means that if either the US decided launch an attack or respond to one from North Korea, the F-16s -- which can carry long- and short-range missiles as well as bombs -- could in theory get from Osan Air Base into North Korean airspace in under three minutes.

Like the spy plane pilots, the F-16 squadrons train daily over the Korean Peninsula -- simulating battles during both day and night. CNN watched as a dozen F-16s took off from Osan on a training exercise.

"We don't know when something's going to happen or what we're going to called on to do, so we need to make sure that across the board we're ready to execute, pretty much at any time," Trueblood told CNN. "We prepare every day like tonight is the night."

He compared the role the F-16s would play in a battle to that of an offensive lineman's in American football.

"We go out as the overall package so load up the jet with both air-to-air missiles, air-to-surface missiles, with the HARM (High Speed Anti-Radiation Missile) we would shoot," Trueblood said.

"Our job is to have the enemy target us with both their air-to-air threat and their surface-to-air threat, and we basically protect everybody else, so we want them to target us."

Despite all the rumblings of potential combat, officials from South Korea and the US insist they'd rather talk than resume hostilities with North Korea.

But Pyongyang's defiant stance has caused concern among many that the current war of words could easily escalate into action.

The pilots at Osan Air Base say if it does, they're ready.

"The mission has always been very clear and dictated down to me that we are ready to fight," Trueblood said.