I have only seen this fly once, and I got some spectacular photos of it.  The reason I got such great photos has more to do with the flying skill of this insect than with my skill as a photographer.  The fly would hover in one place for an extended period of time, so I was able to get the focus right as it flew.

This one was getting nectar from a hoary vervain plant alongside the gravel road.

Bomber flies are known to be external parasites (in their larval stage) of alkali bees, a ground nesting bee.

This fly has a very distinctive loud buzzing noise when it flies.