It’s easy to understand the appeal of a “push-button” approach to fighting Al Qaeda, but the embrace of the Predator program has occurred with remarkably little public discussion, given that it represents a radically new and geographically unbounded use of state-sanctioned lethal force. And, because of the C.I.A. program’s secrecy, there is no visible system of accountability in place, despite the fact that the agency has killed many civilians inside a politically fragile, nuclear-armed country with which the U.S. is not at war. Should something go wrong in the C.I.A.’s program—last month, the Air Force lost control of a drone and had to shoot it down over Afghanistan—it’s unclear what the consequences would be.There are some ethical questions here, and a tradeoff between security and the consequences of extrajudicial assassination. As well as interesting psychological problems created by having people go to war during the day and come home to their families at night.
But what's also interesting is that using air power to conduct counterinsurgency is not new; it's not even new in Afghanistan. From Wikipedia:
Following the end of World War I and the accompanying British defence cuts, the newly-independent RAF took up the task of policing the British Empire from the air. It was argued that the use of air power would prove to be a more cost-effective way of controlling large areas than by using conventional land forces. Sir Hugh Trenchard, the Chief of the Air Staff, had formulated ideas about the use of aircraft in colonial policing and these were first put into practice in 1920 when the RAF and imperial ground units defeated rebel Somaliland dervishes. The following year, in 1921, the RAF was given responsibility for all British forces in Iraq with the task of 'policing' the tribal unrest. The RAF also saw service in Afghanistan in 1928, when following the outbreak of civil war, the British Legation and some European diplomatic staff based in Kabul were cut off. The operation to rescue them, the Kabul Airlift, was the first evacuation of civilians by air.
Arguably, the pacification of these areas by the British shows how purely air-based strategies can work. On the other hand, the fact that America is still fighting in tribal conflicts in Somalia, Afghanistan, and Iraq--essentially, taking over previous British entanglements--suggests that these are not good long-term solutions.