1) Airbus developed the A380 superjumbo jet in response to the market need for larger aircraft to serve high-traffic routes between emerging markets. 2) Boeing's Sonic Cruiser project was an attempted response to the A380, but it was cancelled due to market pressures favoring more fuel efficient aircraft. 3) Game theory principles like the prisoner's dilemma were factors in the strategic decisions by Airbus and Boeing, as each tried to avoid being left behind if the other moved first to develop very large aircraft.