Story highlights

CNN gets exclusive access to U.S. aircraft carrier involved in joint military exercises with S. Korea

U.S. commanders say annual exercise serves as powerful deterrent to North Korea

But this has not stopped Pyongyang from flexing military muscles

Aboard the USS John C Stennis CNN  — 

With a deafening roar of jet engines and an explosion of steam, an F-18 Super Hornet catapults off the deck of the aircraft carrier, and veers up into the sky. Seconds later, another fighter jet shoots out down a parallel runway.

The aircraft carrier USS John C Stennis leads a strike group of approximately 8,400 pilots and sailors, three destroyers, a tanker ship as well as dozens of fighter jets, reconnaissance planes and helicopters.

At a time of