"Recently, I tinkered around with €1 fares because I was bored - but I learnt something significant from it. The base demand for passengers between 2 airports actually increases the lower the prices go. So despite the €1 undercutting, an equilibrium will eventually be reached. So to reduce the effort resetting the same routes over and over again, start undercutting by €20 or more so that the equilibrium is reached quickly, instead of painfully €1 by €1. "
Yes, that is the basic law of demand. In reality, airline routes will, in the long term, adjust to the highest price that airlines can get based on demand, their capacity and the market capacity. Dropping prices by $1 is silly. The good players match the prices to the lowered value of their competitors when they bring in larger aircraft or drop it to a price where the market will roughly sustain the demand. Nice you're seeing this. It's fun messing with the less intelligent players who don't get this. I have one guy who'll put an argosy commuter on one of my routes with 3 routes per day. I take my single drop cheap as hell aircraft and quickly drive the market price to nothing. He's too foolish to listen to my advice, so I'll let him enjoy the <$100 DOP he'll get from that plane.