Washington (CNN) -- The military is dramatically upping its investment in drones over the next nine years, according to Pentagon plans.
In the Pentagon's 30 year plan for aircraft procurement, medium and high altitude unmanned aircraft like the Global Hawk, Predator, and Reaper will balloon in number to 650 in fiscal year 2021, up from approximately 340 in fiscal year 2012.
According to the plan the spike is based on need experienced during recent military operations.
The emphasis on unmanned aircraft "is a direct reflection of recent operational experience and combatant commander (COCOM) demand," the aviation plan states.
And what does that refer to? Just a few examples: There were 118 drone strikes in the al Qaeda and Taliban heavy Pakistan-Afghanistan border region of North and South Waziristan in 2010, up drastically from about 50 in 2009, according to a count by the New America Foundation. So far this year there have been 35 strikes in that region.
Every day these systems are being flown by the U.S. worldwide. Drones are used for multiple purposes such as flying over convoys or forward operating bases in Iraq or Afghanistan and providing vital surveillance on insurgents planning ambushes or planting improvised explosive devices, IEDs, on the road ahead.
Al Qaeda leader Osama Bin Laden's compound was watched overhead by a stealthy unmanned aerial vehicle, the RQ-170, before Navy SEALs raided the residence, according to Peter Singer, a robotics warfare expert.
Singer says the high altitude flying Global Hawk was called in to collect images of Japan's Fukushima nuclear power plant after the devastating earthquake caused many of the plants reactors to go into distress. It has been used in other natural disasters as well, tracking down refugees in Haiti and spotting wild fires in California, according to Singer.
Predator drones are also used on the U.S. border, tracking down illegal immigrants and drug smugglers.
An advantage to using drones is the persistent surveillance they provide, having the ability to hover over a target for hours on end. National security expert John Pike likens it to an FBI stakeout of a gangster's social club.
"For strikes in Pakistan drones are important because they simultaneously provided persistent surveillance," says Pike. "You can stake out a target for a long period of time and then when you have decided to attack the target, you can do so quickly."
And another obvious benefit-- using unmanned drones allows the military and the CIA to avoid US casualties. "You avoid body bags, hostages, and public attention," says Pike.
But a new report is calling on the military to rely less on drones for counter insurgency intelligence, saying more ground based, human intelligence is needed.
The Defense Science Board, a federal advisory committee that advises the Defense Secretary, claims that when talking to Pentagon senior officials about counter insurgency efforts, discussions frequently turned to new technology systems, leaving out other intelligence gathering methods.
A warning though from Pike who says intelligence gathered on the ground can be flawed. "The difference is that human intelligence can lie," Pike cautions. "A standard caveat that is used with respect to human intelligence is that the source may be intending to influence rather than inform. In Afghanistan and Pakistan you may see people trying to use the US to settle grudges."
But Singer says the criticism isn't about cutting back the purchase of more robotic technology. On the contrary, Singer says drones, which until recently were considered slightly exotic, will now be the new normal, especially for troops in the field who have become accustomed to having them.
"The report is about problems in our intelligence collection strategy. If you just have overhead surveillance, whether it's coming from a Reaper that's unmanned or an old spy plane, you are only getting one angle," says Singer. "The best combination is having overhead intelligence and human intelligence, where a network of people on the ground are at work. But that conclusion doesn't lead you to say I'm going to buy less Reapers moving forward".
Singer also thinks that the procurement plan is underestimated, not taking into account future demand for unmanned aerial vehicles and changing technology.
Singer points out the U.S. plan will adjust to what others do. "Our plan doesn't exist in a vacuum. There are 44 other nations that are building and buying military robotics. Some of those nations are allies but others are either current or potential adversaries like Iran, Pakistan, China, and Russia," said Singer
The procurement plan numbers released only focus on the larger, higher speed unmanned aircraft, and leave out the smaller systems the US has and plans to purchase. In total, the US currently has 8,000 drones of all sizes and capabilities.
As for the future of manned aircraft, Singer says there isn't one research and development team at defense supplier companies that is working on piloted planes.
The U.S. military's inventories of manned aircraft are expected to remain at present levels into the future with the number of fighter planes declining about 10% over the next ten years.