U.S. embassy officials have met with aviation officials throughout Africa to try to track the plane, as spy satellites have scanned airstrips around the continent.
After sitting on the tarmac for 14 months, the plane took off on May 25 and has not been seen since, reports The Washington Post. The pilot did not respond to calls from the control tower as the aircraft soared off the runway.
Officials caution that the Boeing 727 is most likely the focus of a business dispute or conventional criminal enterprise, says The Post. But in the aftermath of the September 11, 2001 terrorist attacks, agencies cannot take for granted that the plane will not be used as a weapon against civilians.
If the plane was not stolen by terrorists, it could be sold to them. "It is not a stretch to think this plane could end up in the hands of terrorists. A number of companies involved in gun running [and other crimes] in Africa have indirect ties to various terrorist groups," Chris Yates of Jane's Aviation service told the newspaper.
And even if this particular aircraft is not acquired by a terrorist group, the incident raises questions about African airport security in general, The Post said.
Those questions are particularly pressing now, after terrorist attacks in Kenya and Morrocco over the past year. The November hotel bombing in Kenya, which killed 16 people, and the blasts in Casablanca last month, in which 42 died, follow the 1998 attacks on U.S. embassies in Kenya and Tanzania that claimed 231 lives.
Terrorists in Kenya in November also tried to shoot down an Israeli airliner with a shoulder-fired missile. Last month, Britain, the U.S. and other countries warned of a possible imminent terrorist attack in Kenya.
Aerospace Sales, the company that is the last listed owner of the plane, has a somewhat murky history, The Post reports.
Maury Joseph, president of Aerospace Sales, was convicted in 1997 of forging documents and defrauding investors in a different company and was banned from running a public firm.
Lance Joseph, son of the company president, told The Post the plane was leased by a company who name he couldn't recall that removed the seats and installed fuel tanks in order to transport fuel to remote airfields.
That firm brought the plane to Angola, Lance Joseph said. But Angola wouldn't let it take off again because it did not carry the right documentation, and wanted to collect large fees and outstanding private claims on the plane.
The Josephs apparently had a business dispute with a Miami aircraft broker named Mike Gabriel who, Joseph said, had gone to Africa and talked of trying to claim the plane. Gabriel was convicted in the 1980s of importing 5,000 pounds of marijuana.