You can't change the laws of physics. Energy is proportional to velocity squared. Thus, to go to 1.8M, it will be a lot more expensive. Airframers might be able to build a 1.8M aircraft significantly more efficient than Concorde. However, it does not change the fact that the supersonic aircraft will be a lot more expensive to operate than any contemporary subsonic jets. 0.98M seems to be a good compromise. That is, the increase in speed has the potential to allow airlines to significantly increase productivity. Hence, it will more than make up for the additional fuel costs. This means airlines can offer slightly faster services at about the same cost. If a passenger can pay the same price and fly 15% faster, I think most will choose a faster flight. Without an increase in productivity, a 0.98M aircraft will not be economically viable. Boeing's business case, I believe, is strongly hinged on the pontential to drastically increase the productivity of each aircraft. That's why airlines are interested in the proposal. Airlines may want higher speed, but when they see all the numbers, almost everyone will come to the same conclusion that a 1.8M aircraft would not be cost attractive. Not a single all-premium service has proven to be successful, and I doubt a 1.8M aircraft would reverse this trend.
[ 09 December 2001: Message edited by: casual observer ]