I was a regular (frequent?) user of the Stansted - Prestwick route over the years it operated having completed an estimated 70 to 80 trips. In the early days I feared that it would not last long - I remember flying in a 737-200 with only 16 other passengers. But the loads improved and for many of the years I witnessed load factors of 80 to 90%. The drastic reduction in frequency during the final years reducing from a peak of 10 round trips to only one, made it unattractive to me as most of my journeys were same day returns. As I tended to fly on early and late flights I did notice a good proportion of business passengers. The fares were not an important factor for me just frequency and convenience. For most of the time the route operated (over 16 years) it had competition with EasyJet on the Glasgow-Stansted route. My guess is that there would be enough support for a sensibly timed service linking a London airport with Prestwick. The 737-800 was possibly just too big for the route and I appreciate that the escalating APD charges would have made considerable inroads to the economics of the route. I would certainly use any service that provided the faciliity of a day return.