Obviously, that one airbase is a target, and a major one. If Vangoria wants any sort of advantage, we need air superiority. Therefore, the goal would be to pillage and steal the fruits of that base and then salt the earth (burn the f**ker down). An ISIS-reminiscent façade ("We want to establish a separate nation and will slaughter any in our way") could work in the ways of fending off suspicion. Of course, the King could never be seen, by any circumstances. His very cooperation financially would reflect badly on Vangoria, let alone actual physical involvement (that would be hellish for publicity). Therefore, the best idea would be a slow rise to power. The Elite Military (in disguise as a terrorist cell) begins infiltrating and devastating nearby regions, stealing tech and weapons, while at home Vangorian regulars train with the new tools for a full-blown war, where a highly trained and armed-to-the-teeth army fights alongside superhumans against the world (I will need some heavy body armor for protection against bullets, while not overly hindering my movement. I'll let you figure that out, though I suggest boron carbide plating and Kevlar, allowing for fluid movement while protecting against high-caliber rounds). Of course, we're starting out in the Mediterranean, and the not-too-rich part of it. Albania, Bulgaria, Vangoria, FYRUM. All countries who cannot provide much in the ways of advantages. Which raises another question: How far is Vangoria hoping to expand? I mean, all kings and emperors have ambition. But some have more than others. And if we're talking the next Alexander the Great who wants a new world empire, we might want to consider some high-priority targets, like military bases in Germany, Italy, and France (are those still world powers?) where major manufacturing would take place. In short, high-risk-high-reward for trying northern, north-western European countries, low-risk-moderate-reward for expanding south, southeast into Asia and the Middle East. There's definite reward in the form of Middle Eastern oil reserves, which could work easily to Vangorian advantage (I recall a story from The Stormlight Archive's "The Way of Kings": The girl Shallan's family was one of nobility, but was rather poor due to bad management and one of her brother's gambling problems. Then, out of nowhere, more and more quarries begin appearing on her father's land, driving them into a life of affluence. This was, of course, due to a magic item known in the series as a fabrial, which her father had borrowed from a secret society in order to convert empty tracts of land into productive quarries. We could use this same miraculous excuse in Vangoria for sudden sales of petroleum: The country had recently uncovered oil wells and were exploiting them to their fullest extent, while not letting any other countries witness the actual mining, thus hiding the fact that it was actually stolen from, say, the United Arab Emirates, or Kuwait) by simply selling it for a low price on the European market, and then using the money to buy or kick-start national manufacturing of weapons and vehicles for correspondence with the above strategy.
Also, GET BACK TO WORK (after responding)!!!!