Go to a career fair and you'll be accosted with fliers or leaflet advertisements for the many companies there. Often fliers are a waste of paper because they get thrown away.
Just like the paper fliers that people hand to you on the street that end up flying into a trash cans, a flier can also mean someone who flies or travels by air. You might also see the word spelled flyer, which works too. A frequent flier is a person who travels a lot. Get enough frequent flier miles on an airline and you could fly somewhere for free.