They're interesting people to consider, people I could learn from, who I have learned to appreciate in their relevant works. Usually, I find the personality of female characters more interesting. Heck, I suppose that among the characters, there'd be Modesty Blaise and Willie Garvin. For those... I really, really hope they'd be willing to consider listening and not killing me outright, because those two are scary, in the sense that they try to not take unconsiderate risks when they can avoid it, and they are extremely lethal if provoked. You should check their books/comics, BTW.
I'll concede that I have a liking for characters who tend to keep their strengths in check and are more than willing to talk before going for violence. Female characters fit this description way more often than male ones, I found out over the years (Willie Garvin, of the Modesty Blaise comics, though, is one of these). Colonel Blair would be less of a threat unless he is in a cockpit, but if he is... ouch. Overall, though, remember that I'm mostly attracted to personnalities, and that I like to talk, to discuss, to learn, more than I consider physical attraction a thing.
EDIT: for the last one, I'd probably say Yoko Tsuno. She has been a staple of my comic book life for decades and a pretty good role model of an engineer.