The recent comments are somewhat amusing to read. While I can see a long-term strategic rationale for keeping Prestwick open (e.g. cargo, military, and back-up against fog), I'm struggling to figure out which passenger airlines would likely want to fly to Prestwick, apart from Ryanair. The only airline I can think of is Wizzair but they moved to Glasgow Intl less than a year ago.
I'm sure those who are much more familiar with Prestwick will have a good idea as to potential passenger airlines - would someone more knowledgable than me be kind enough to suggest names of these airlines and perhaps even some routes ?