But the Delta expansion never happened. Only the flights to Abuja started. Much to everyone's shock—including Delta itself—the U.S. Transportation Security Administration refused to give the airline permission to fly to the other places. No one even knew the TSA had the legal right to block service, and its authority in this area has never been tested.

"Delta really got screwed," said an executive who works at another U.S. airline. "To call it a TSA overreach is an understatement. When you start telling us where we can't fly, it's like telling us to give our customers to the competition."

But since no carrier argues publicly with the TSA, Delta meekly "delayed" its plans. And one of the carrier's public relations executives went out of his way last week to call the TSA "a great partner" when he told me that Delta hopes to finally launch service to Monrovia in September.

The gap in the U.S. carriers' route maps creates opportunities for the European carriers to grab traffic and make it nearly impossible for the U.S. airlines to launch competitive nonstop service into Africa.

Take Lufthansa, for example. While Air France tends to carry U.S. travelers to former French colonies and British Airways is strongest to former British colonies, Lufthansa has pursued an Africa-wide strategy. Via Frankfurt and Munich, it operates 104 flights a week to 16 destinations in Africa. But its subsidiaries, including Swiss International, Brussels, Austrian, and BMI, operate 118 more. That makes a total of 222 weekly flights to 33 cities in Africa.

The result? Year-over-year demand from U.S. travelers using Lufthansa service to Africa has jumped 25 percent. Even if you attribute 10 to 12 percent of that growth to the recovering economy, a Lufthansa spokesperson says, that means fundamental demand is growing by as much as 13 percent.

And even Africa-based airlines are growing. Now part of the Star Alliance, South African Airways is trusted by U.S. travelers. Ethiopian Airlines also flies to the United States, as does Royal Air Maroc of Morocco and Egyptair. And a new airline called Arik Air now flies three times weekly to Lagos, Nigeria, from New York.

Arik Air is privately owned and is emerging as Nigeria's de facto flag carrier. Its equipment is new—Airbus A340-500s equipped with lie-flat beds in business class and coach seats with an extremely generous 37 inches of legroom—and Arik can draw on the large market of ethnic Nigerians living in the United States as well as business travelers.

About 60 percent of Arik's U.S.-originating passengers are headed to Lagos, but others go onward to Port Harcourt, the center of Nigeria's oil community, or Abuja, the capital. They also connect to other places that Arik flies, including Ghana, the Gambia, Benin, and Sierra Leone.

"We already dominate the domestic Nigeria market with about 40 percent market share," explains Bob Brunner, executive vice president of North America for Arik. "We want to be the airline of West Africa."

The Fine Print…

Hightower, the U.S. expat now working from Cape Town, has two tips for newbie business travelers to Africa. "Pack fault tolerant," she says. "There's a high risk of loss or pilferage of checked bags." Also, "make sure you have confirmed reservations for onward connections. Even if you have paid for your tickets, carriers in Africa often require you to reconfirm your reservations three days before departure. If you don't reconfirm, they'll cancel."