Final answer:
To make the sun appear stationary, a plane must fly along the Earth's equator at a speed of 1670 km/h or 1002 mph in the opposite direction of Earth's rotation.
Step-by-step explanation:
To make the sun stand still relative to the passengers on an airplane flying along the Earth's equator, the airplane would need to match the rotational speed of the Earth. The Earth rotates at about 1670 kilometers per hour (km/h) at the equator. To convert this to miles per hour (mph), you can multiply by 0.6, giving approximately 1002 mph. Therefore, the plane must fly at a speed of 1670 km/h or 1002 mph along the equator in the opposite direction of Earth's rotation to make the Sun appear stationary to the passengers.