Why do you imagine that pilots are different from any other group? This is a profession that naturally attracts enthusiasts. Enthusiasts of subjects that don't interest others are often called anoraks. There are probably a slightly disproportionate amount of anoraks (aka enthusasts) in flying, and their conversation, particularly early in their careers, can be a bit one dimensional!
On top of that, male British pilots are often closet railway buffs, car nuts and real ale addicts, with a sideline in serious hifi gadgetry. If these aren't breeding grounds for terminally boring conversations, then I don't know what is.
Scroggs (Railway buff, car nut and AV gadget freak. And lager drinker, so that's alright then)