As Algeria is doing presently, the denial or approval of overflight rights is a powerful tool that states can impose on the United States. These include where U.S. air assets can enter and exit another state, what flight path they may take, how high they must fly, what type of planes can be included in the force package, and what sort of missions they can execute. In addition, these constraints include what is called shutter control, or the limits to when and how a transiting aircraft can collect information. For example, U.S. drones that currently fly out of the civilian airfield in Arba Minch, Ethiopia, to Somalia, are restricted in their collection activities over Ethiopia's Ogaden region, where the government has conducted an intermittent counterinsurgency against the Ogaden National Liberation Front.
A famous example of states exercising overflight rights occurred in April 1986, when President Reagan authorized airstrikes against five sets of targets in Libya, in retaliation for its involvement in the bombing of a Berlin disco that killed two American servicemen. French Prime Minister Jacques Chirac and President Francois Mitterrand refused to permit the U.S. F-111 attack aircraft to fly over France because they did not believe the airstrikes would deter future Libyan support for terrorism; Mitterrand told U.S. diplomats that it should not "do a pinprick" against Libya. Similarly, Spanish Prime Minister Filipe Gonzalez refused to authorize access to his country's airspace, but recommended that F-111s simply fly through Spain anyway and his country would "pretend not to see them." The Reagan administration passed, flying the sortie instead through the Straits of Gibraltar. Though the airstrikes against Libya largely succeeded, the costs, risks, and length of the operation were increased because the French and Spanish governments refrained from supporting the raid.
When the United States does not receive permission to fly over another country's airspace, it runs the risk of pilots or aircraft being killed, captured, or destroyed. This includes the May 1960 shoot-down of the U-2 surveillance plane over the Sverdlovsk area of the Soviet Union, or the December 2011 downing of an unarmed RQ-170 Sentinel drone over eastern Iran. In both instances, the United States had been flying overhead without permission for years, having decided that the intelligence collection objectives outweighed the risks of being caught.
Now, the United States assuredly has other tricks in its military bag -- advanced capabilities, not yet public, that could be used to bypass the need for overflight rights. The CIA or the Pentagon could probably use those capabilities to find and attack militants in Mali or elsewhere. However, the Defense Department often strongly opposes using still-secret intelligence collection or weapons platforms on military raids because their use might make them public -- or worse. If they were lost on the battlefield, advanced technologies could be sold to Russia or China and potentially reverse-engineered. That's why at various times the United States has refrained from using cruise missiles and stealth aircraft, even when they could have done the job. Any U.S. operations in North Africa would have to be of the highest priority to justify the potential revelation of cutting-edge weapons.
Those who see a military tactic used with apparent success in one state often ask why it cannot be used to confront a comparable challenge in another state. This tactics-first approach to foreign policy is routinely advocated by pundits and policymakers in Washington. Setting aside the essential question of whether that tactic can achieve the intended political or military objectives, the state that the United States must fly from, or fly over, could simply forbid it. That's their sovereign right. The White House can choose to act -- in Algeria or elsewhere -- without a state's permission, and deal with the political consequences and likely reduction in diplomatic and intelligence cooperation if U.S. involvement is exposed. Given that 94 percent of the Earth's land mass is not U.S. territory, the sovereign right to say "no" is one that advocates of using military force must keep in mind.