These days with all of the advanced planning tools used in filling routes there are many times when pilots will refuse directs because it will actually be longer. DL and FedEx are the biggest that come to mind that don't always want to go off of the planned route on transcon flights. As far as speeding up, they do sometimes do this, but depending on the city pairs it doesn't always do that much. As an approximation, increasing mach number at cruise increases ground speed by about 7-10 knots per .01 mach (M.79 about 7 knots faster than M.78). A typical B737/A320 will cruise around M78 and very rarely do i see more than M80 or occasionally M81 (especially on long flights, burns to much fuel). Another way to increase ground speed at the expense of fuel is to stay lower; M78 at 30,000 is faster than M78 at 36,000 (ignoring wind differences).

I think the author of the article used wheels off compared to scheduled departure for departure delay (which it shouldn't be) and used arrival at gate to calculate flight time (which it also shouldn't be). To get accurate comparisons it should be based on Off to On for flight times (the out and in aren't usually anything the pilot can do) and really needs to account for time of day for taxi delays being different. everyone that's flown out of JFK during 'rush hour' knows how long the wait for takeoff can be as opppsed to the slack times during the day.

Still an interesting read, thanks for posting.

Dan