U.S. troops are pinned down in a crowded city center. Several are wounded and need immediate evacuation. There are miles of labyrinthine roads and thousands of enemy gunmen between them and the nearest base. The threat from rocket-propelled grenades has grounded the big helicopters.

In the race to build a so-called personal flying machine, few developers have got much past the tethered-hop stage, with promises of one in every garage sometime soon. Generations of hopeful flyers have died waiting. But Israel's Urban Aeronautics at least addresses a key point: A machine like the X-Hawk concept shown here (which the company recently released, saying it's the design they'll build) has less chance of serving your average frustrated commuter's needs than of playing a utility role in commercial and government transport. Projected uses include urban rescue, repair and patrol.