FAB - as Wader says, it's irrelevant. We had a qualified barrister on my course, who'd read Law, not surprisingly. He ended up on the Sea Harrier and is now a grande fromage in BAe.
My daughter is lining herself up for aircrew, and will be reading Zoology and Psychology next year.
What is of far greater interest to the interviewers is the use made of the time at university. Did they sit around for three years doing the minimum and watching Countdown, or did they get out and make something of their time, getting involved in the running of a sports team or similar, for example?