Reply #105: Even if you wanted to airburst, it wouldn't be that difficult in a larger city.

[Xithras]

Load it into a van with a cargo ramp, put wheels under it. Drive the bomb to a random skyscraper and wheel the bomb into the elevator of your choice. If anyone objects, shoot them. When the elevator hits the top floor, push the "boom" button.

Even going up a few hundred feet is enough to substantially increase the blast radius. And most buildings don't have much security on their elevators.