Pidgey

The first couple dozen pokemon were never meant to be anything mind-blowing; they filled the roles of fairly mundane animals, giving us a little taste of the setting and its rules before we got into the flaming snails and flying magnets. Pidgey is this generation's most basic "flying" type pokemon, or rather normal/flying, an extremely common type combination.

In fact, for the longest time, no pure-flying pokemon ever existed, which I honestly thought made sense; the "flying" type doesn't represent what a pokemon is comprised of, but what a pokemon happens to be doing. It has to be attached to another type to represent what sort of creature is actually doing the "flying" here, so "normal" type was kind of its bare minimum.