The duopoly refers to Airbus and Boeing – between them accounting for at least 90% of new aircraft deliveries, month after month. These two OEMs are very important companies. What happens to them impacts your world.
Until quite recently these two companies were relatively equal in terms of market share. Game theory dictates this balance is the optimal way for the duopoly to remain stable. Over the recent past this balance is gone, the duopoly is unstable and it is getting worse. Look at this chart.