Some of the companies that are more heavily dependent on the military and the aid economy, like construction and logistics businesses, are trying to stay put by reconfiguring toward the few areas where analysts feel Afghanistan might have growth potential, like mining or trade.

But others are nervous that Afghanistan’s nebulous private sector will not be enough to fill the gap left by the United States’ military and development spending. World Bank figures back up those fears: the bank estimates that outside aid is equivalent to more than 90 percent of the country’s total economic activity, and forecasts a slowdown in growth in the coming years to 5 or 6 percent from about 9 percent, or much lower if security worsens.

That is in part because, despite the billions in reconstruction and aid money poured into Afghanistan, there still is no major manufacturing or technology base that could be a driver of future prosperity. A new Pepsi bottling plant on the outskirts of Kabul is trumpeted as one of the few new investment triumphs.

“There is a sense that they have to change from a war economy to a postwar economy, and people definitely expect it to contract,” said Thomas Rosenstock, a lawyer, originally from New York, who helps foreign companies entering the Afghan market. “It’s uncertain how dramatic the contraction would be.”

Then there are those who are voting with their cash.

Each week tens of millions of dollars — some thought to be diverted American aid or drug money — are packed into suitcases or boxes and loaded onto planes leaving Kabul International Airport for destinations like Dubai, capital flight that is increasing steadily ahead of the 2014 deadline, officials say.

Noorullah Delawari, the central bank governor, recently imposed restrictions limiting the amount a passenger can take out of the country to $20,000 a trip.