It used to be the joke...
It used to be the joke, during labor contract negotiations, the we would all work for tips and tips alone. The company hated that idea. But, one guy crunched the numbers and figured he'd make more money if we worked for tips.
I suppose this is possible. Figure 800 hours per year of flying, two-hour average segments, that's 400 flights a year. Multiply that by an average of, say, 150 passengers per flight...that's 60,000 passengers per year. If each passenger averaged $5 USD per tip...that's $300,000 USD per year in tips. Split it with your fellow pilot. Not bad....
As an aside, we also used to tell the company during labor contract talks, that we should be paid a percentage of what the CEO makes. Say, like maybe 1%. So, if the CEO makes (total annual compensation) $35M per year (This is not unusual here in teh U.S.), that's $350,000 for the pilots.
Of course, the tip compensation scheme wouldn't work these days, as the level of airline service is dreadful (in the U.S. it is....possibly not so elsewhere in the world), and most passengers would rather punch the airline workers in the face rather than give a nice tip.
Pantload.....