Is there an online source that will show me all flights, with schedules, leaving east coast airports for specific UK airports? That is, something that shows, for any given day, all the flights leaving the east coast for Gatwick, or Prestwck, etc.
Try the Official Airline Guide (OAG) at http://tinyurl.com/hdnxl. It offers various combinatios of routes, destinations, etc, that you can search
Many airports also post more detailed info from the OAG site on their websites.