IS IT FLIER OR FLYER?

HANDS up if this is one of those things that you’re never quite sure about?  We weren’t.  Well, you can relax.  It’s both, or is it either?  Anyway, you know what we mean.  They both mean leaflet, you know, the things that annoying people in the street force into your hands in a bid to get you to go to the gym or the new Lebanese restaurant round the corner.  “Flier” is more popular apparently.  Now you know!