In an interview on the sidelines of the exercise, Maj. Gen. J. Marcus Hicks, the head of American Special Operations forces in Africa, put it this way: “This is an insurance policy that’s very inexpensive, and I think we need to keep paying into it.”

Building a new base in this remote, landlocked country nearly twice the size of Texas marks the latest chapter in the military’s contentious history of drone operations around the world.

It comes as American drone strikes are on the rise again, after tapering off somewhat in places like Pakistan. The number of American strikes against Islamist militants last year tripled in Yemen and doubled in Somalia from the figure a year before.

Last month, an armed drone flown from a second base in Niger killed a Qaeda leader in southern Libya for the first time, signaling a possible expansion of strikes there.

Where American and Nigerien officials see enhanced security in drone operations — for surveillance, strikes or protecting Special Forces patrols — others fear a potentially destabilizing impact that could hand valuable recruiting propaganda to an array of groups aligned with Al Qaeda and the Islamic State, and that could increase the militants’ menace.

“Eliminating jihadi military leaders through drone operations could temporarily disorganize insurgent groups,” said Jean-Hervé Jezequel, deputy director of the International Crisis Group’s West Africa project in Dakar, Senegal. “But eventually the void could also lead to the rise of new and younger leaders who are likely to engage into more violent and spectacular operations to assert their leadership.”

A rare visit this month to Air Base 201, the largest construction project that Air Force engineers have ever undertaken alone, revealed several challenges.