For several years, other air taxi companies have opened up using new, efficient, and relatively fast and comfortable small propeller planes, notably the four-seat Cirrus SR-22.
I've paid particular attention to SATSAir, which like DayJet is based in the Southeast. This week it announced that it had flown 16,000 such Cirrus trips in 2007, a 60% increase over the year before. Its press release made a point similar to what I heard at DayJet:
Traditionally, the use of the air cab service has been a remedy for driving trips of 2-5 hours, not a replacement for other forms of air travel. However, 2007 saw a shift with a significant number of new SATSair customers using the point-to-point air cab operation as a solution to their hub-and-spoke airline frustrations and woes, in fact decreasing the door to door travel times.
Several economists and aviation experts have written me to say that, in principle, the air taxi model just can't work in the long run. Too expensive; market too small; and so on. Could be. I'm just reporting that at several companies it's working now.