Blue Angels 4 ship "break,break,break" at Sea Fair, Seattle 2011. Notice the water condensation in the strake vortices during this tight maneuver.
The "Blues" F/A-18 aircraft are former fleet aircraft that are nearly combat-ready. According to the Navy, they can be repainted and readied for combat service in just 72 hours.Significant modifications to each aircraft include removal of the aircraft gun and replacement with the tank that contains the paraffin-based smoked oil used in demonstrations, installation of inverted fuel pumps to increase the time aircraft can spend inverted without fuel starvation, and modifying the control stick spring system that is used to facilitate more precise aircraft control inputs.
The standard demonstration configuration is such that the pilot must overcome 40 pounds (18 kg) of nose-down stick input to maintain level flight. The Blue Angels do not wear G-suits, because the air bladders inside them would repeatedly deflate and inflate, interfering with the control stick between the pilot's legs. Instead, Blue Angel pilots tense their stomach muscles and legs to prevent blood from rushing from their heads and rendering them unconscious.
Canadian Airline Blog