If you want direct non-stop then nothing is available for your dates unless Globespan announce Glasgow -Sanford flights for the Winter which include those dates. As yet they have only committed to a flight schedule up to end of October.
You are really looking at scheduled flights from Gatwick, Heathrow or Manchester with a connecting domestic flight from Glasgow/Edinburgh or possibly AA or Continental with a change in the US, but I'm not sure of their winter schedules.