Complex sentence: Because human senses are adapted for use on the ground, navigating by sensory input alone during flight can be dangerous: sensory input does not always accurately reflect the movement of the aircraft, causing sensory illusions.
Split into simpler sentences: Because human senses are adapted for use in the ground, navigating by sensory input alone during flight can be dangerous. Sensory input doesn't always accurately reflect the movement of the aircraft, causing sensory illusions.