Pilots' uniforms usually show some sort of rank, so this is even crazier to me.

FYI, the rank doesn't really mean anything; it's a position identifier. The captain of the plane will have four stripes, just like the captain of a ship. The copilot/first officer will have three. The flight attendants wear a completely different uniform and don't have any.

In the airlines, everything is about position and seniority. The most senior captains will make the most money and have the most choice in their schedules.

I had a buddy that was a senior copilot at once of the major airlines, and when he first upgraded to captain, he actually fell further down priority list when choosing their schedule because he went from one of the most senior copilots to the most junior captain. Of course that's temporary, and the move opens up far more potential for earning and greater seniority down the line.

I have no idea about seniority at the regional airlines, which pay people like shit and are generally just used as a feeder to getting a job at one of the big ones. If you have a decent mid-level white color job, you probably make more than a pilot on a regional airline.