I crossed paths with somebody wearing a U.A. hoodie today. This inspired two thoughts — first that anime merchandising has come a long way, that once upon a time you would have had to pay an artist at a convention to make such a thing for you, whereas now it's an "off the rack" item ; second that, whatever the rationale the name may have in the show, "U.A." is simply an inversion of eiyuu "hero", the sort of wordplay the Japanese delight in.