This book is a military thriller. The cover features a high-tech stealth fighter of some sort. The context shows that the action is more of an Air Force sort of theme, though I haven't read the book so I can't say for certain.
From the Back Cover:
GUARDIAN: Created to fuel their deadly new military machine, GAURDIAN is the united Germay's top-secret energy project hidden deep in the Arcitc waters off the coast of Greenland. Despite its potential for global destruction, they'll protect it at any cost - even if it means World War III.
GLOBAL ALERT: Panic strikes the nations of the world as satelite intelligence confirms reports that GAURDIAN'S massive heat bomb is about to explode below the polar ice. Disaster threatens millions unless the lethal fireball is found and destroyed.
DELTA BLUE: THEMIS is America's awesome space platform in permanent polar orbit and headquarters for the elite stealth fleet of skyfighters lead by Delta commander Colonel Kevin "Snake Eyes" McKenna. They are the only force that can break through to GAURDIAN in time to save the future of the planet!