The Italian Air Force lost one of its RQ-1A Predator UAVs when the unmanned aircraft crashed into the sea, after losing contact with its operator. This is a common cause for losing these expensive ($5 million) remotely operated aircraft. Unmanned aircraft have a much higher loss rate than manned aircraft. The RQ-1 Predator has an accident rate of about 30 per 100,000 flying hours. Older model UAVs had much higher rates (up to 363 for the RQ-2A). Communications has turned out to be very difficult to maintain at a very high level. But progress has been made in developing better robotic flight software, to fill in when communication is lost.
Manned combat aircraft, meanwhile, are becoming much more reliable, even as they become more complex. For example, in the early 1950s, the F-89 fighter had 383 accidents per 100,000 flying hours. A decade later, the rate was in the 20s for a new generation of aircraft. At the time, the F-4, which served into the 1990s, had a rate of under 5 per 100,000 hours. Combat aircraft have gotten more reliable and easier to maintain, despite growing complexity, for the same reason automobiles have. Better engineering, and more sensors built into equipment, makes it easier for the user, and maintenance personnel, to detect potential problems. Aircraft used the computerized maintenance systems, currently common on new aircraft, long before automobiles got them. Unless you have a much older car that still runs, or a real good memory, you don't notice the enormous increase in automobile reliability. But older pilots remember, because such changes are a matter of life and death if you make your living driving an aircraft. And commanders know that safer aircraft give them more aircraft to use in combat, and more aircraft that can survive combat damage and keep fighting.
UAVs like the Predator have reduced their loss rate by using automated landing and takeoff software. This approach is often used on manned aircraft, but is more useful on unmanned aircraft, since a pilot on board can "feel" the situation more accurately for landings and takeoffs. Many UAVs are also improving their automatic (robotic) flight software. Some models will simply turn around and return to where they started, if they lose communication with their operator. The Predator is in the process of getting a lot of this new flight control software, because without a pilot on board, these aircraft need all the help they can get.