Indian President Pratibha Patil flies in fighter jet. Here is the photo from Manorama, that fails to show who is sitting inside. The speed of the aircraft is mentioned as 700-800 km per hour, but in fact Sukhoi is capable of flying at higher speeds.Indian President wore a G-suit for the flight. Manorama reports earth's gravitational effect is very large when you fly at a higher level and this suit helps you to maintain the normal blood pressure.
In reality gravitational effect diminishes as you move farther.
The G-suit has nothing to do with earth's gravitational force. It helps you deal with very high acceleration.
The news as reported by BBC. The highlighted lines give a better explanation.