What three symbols of American life do terrorists often target using aviation?

Terrorists often target symbols that represent the core values and structures of a nation's identity. In this case, free enterprise represents the economic freedom and capitalism that are fundamental to American life. Military infrastructure symbolizes national defense and the ability to protect the country. The democratically elected government stands for the political system that allows citizens to participate in governance, emphasizing the principles of democracy and representation.

These targets are significant because they directly challenge the values that America's way of life is built upon. Striking at these symbols can lead to a greater impact on national morale and provoke a larger political response. The choices provided, while they include various aspects of society, do not encapsulate the specific symbols of American life and the principles that terrorists aim to undermine through their attacks.