Advances in unmanned aircraft (UAVs) technology have led to an enormous increase in effort to bring more models into service. While the United States has dozens of UAV models in service, or development, 41 foreign nations operate over 80 different UAV models. Moreover, 32 nations are developing twice as many new UAVs. But the United States is unquestionably in the lead, with plans to spend over $15 billion in the next six years on UAV development projects. About a third of that money is going into developing combat UAVs (UCAVs). Actually, several current UAVs are already carrying missiles. But the new UCAVs will operate more like current jet fighter-bombers, not the slow moving recon UAVs that are currently firing missiles from time to time. A maritime UAV is being developed, as well as ones that can stay in the air for days at a time. Over a billion dollars is going into improving the most successful current UAVs, like the Predator. Meanwhile, the number of UAVs in American service is expected to grow from under a thousand today, or several thousand by the end of the decade. Most of these will be micro-UAVs, weighing under ten pounds each and used by combat troops at the company, platoon and squad level. But most of the money is going into UAVs that weigh the same as manned aircraft, but do much more.