Income trajectory is defined as the growth of an individual’s income over time. Think of a line on paper moving through space from the bottom left to the upper right and back down again.

A trajectory or flight path is the path that an object with mass in motion follows through space as a function of time.

At some point, the line will reach a peak and begin to decrease. This is your income trajectory. It’s different for each person and is based on their experience, education, location, gender, ability to network, etc… https://www.firethefamily.com/home/income-trajectory