Yeah, George Michael was popular here. I remember a lot of Wham tshirts in the 80s.

I've always thought that her guilty pleasure may be some of the hair metal bands from the '80 like Def Leppard, Bon Jovi, and Guns and Roses. But I can see her being very embarrassed if anyone caught her listening to them.
On the not quite as cheesy side I can see her liking Aerosmith and John Mellancamp. I can see her tearing down the road on her Indian to an Aerosmith or Mellancamp tune. I've seen a lot of fic where people have her listening to country but I've never got seen that unless maybe it was outlaw country. I guess because of the bike and leather pants I see her enjoying harder stuff than you might think from the straightlaced Air Force officer. She need some sort of outlet to be wild or she would combust.

I also sort of see her listening to David Bowie. He had a lot of space themed music. A kid wanting to be an astronaut could be entranced by Space Oddity.

Hmm, Maybe the Eurhymics/Annie Lennox too.

And of course, U2, simply because I cannot fathom anyone not loving them. ; )