Agglomeration economies are real, so there could be big gains from technologies that help people transport themselves more quickly and cheaply to areas and with populations where their productivity is higher.

FORBES: Will Hoverbikes Be More Important Than Tacocopters?

British Prime Minister David Cameron agreed to "provide logistical military assistance to help transport foreign troops and equipment quickly to Mali, " but no British personnel in a combat role, a Downing Street spokesman said.

CNN: STORY HIGHLIGHTS

Hollande spoke Saturday evening with British Prime Minister David Cameron, who consented for the United Kingdom to "provide logistical military assistance to help transport foreign troops and equipment quickly to Mali" -- but no "British personnel in a combat role" -- a Downing Street spokesman said.

CNN: STORY HIGHLIGHTS