We airshow photographers love shots with vapor. Give us jet aircraft on a humid day, and we’re poised and ready. Vapor normally occurs when the aircraft reach speeds around 400 mph, and conditions are right. The amount of vapor depend on moister content in the air, and the make up of the plane. Jets with broad wing surfaces tend to develop more vapor and at lower speeds than others. Either way the effect is quite dramatic.
There is another type of shot that to me is more impressive. This shot can only be achieved when the aircraft is right on the edge of breaking the sound barrier. Without getting into the physics of it, this happens at the speed Mach 1.0 (between 662 – 760 mph) depending on weather conditions. When light is right you can see the shockwave created by the plane. I have captured this effect twice here is one of those shots, from 2010 at the Quad City Airshow.