The unmanned aerial vehicle (UAV) market is growing, projected to reach $8.4 billion by 2018. UAVs are predominantly used for military and security purposes by countries like the US, UK, and Israel. While UAV use is concentrated in a few countries currently, the market is becoming more international. The US accounts for over half of research spending and procurement but this share is expected to decline as more countries develop and use UAVs for defense. The UAV market is led by high altitude vehicles but medium and low altitude types are growing segments. Increased civilian and commercial use of UAVs is also expected in the future.