Several years ago, a friend and I each had an older plane that we wanted to get rid of, but neither were sellable. So we went out to the field and tried to have a mid-air. We tried for head-on's, convergence, over-taking, dive-bombing, combat style ... everything we could think of. This went on for several flights. Although we got close at times, we succeeded miserably. Finally, we gave up, and plowed the planes into the grass.

Mid-air collisions only happen when they are not intended.