In Martin Luther King Jr.'s metaphor from his Nobel Prize acceptance speech, he compares the ground crew of a flight to:
1. The people who work behind the scenes and are essential for the success of the journey.
2. Those individuals whose labor and sacrifices may go unnoticed but are crucial for the freedom and progress of others.
3. The unsung heroes who support and enable the visible leaders, like pilots, to achieve their goals.
King uses this comparison to highlight the significance of those who may not receive public recognition but play a vital role in enabling progress and success. This metaphor emphasizes the importance of acknowledging and honoring the contributions of all individuals, especially those whose efforts are essential for the advancement of society.