In addition to the vapor trails coming off the wings and fuselage, you can also see the heat mirage from the engines behind the aircraft. In some shots if you look closely you can see it tracing the arc that the plane was traveling.
The combination of fluffy clouds and patches of blue sky made from some great backgrounds.
At one point in the demonstration they do a low-level high-speed pass at just under the speed of sound (Mach 1). They always tell everyone in advance to "get their cameras ready", but that plane is really moving fast. Just as the aircraft gets to the edge of Mach 1 the vapor trail forms a donut around the back of the plane. This is the first time I've caught the whole thing.
Just under Mach 1. They don't want to blow out any windows or set off all the car alarms in the area.
Another fun demonstration to watch is the AV-8B Harrier. This has to be one of the loudest planes at the air show - and it's truly amazing to see.
Here's a sequence showing a vertical take-off.
Click here to see more images from the F/A-18 Hornet demonstration at the 2012 Miramar Air Show.
Click here to see a few more images from the AV-8B Harrier demonstration at the 2012 Miramar Air Show.