Cognomen Айер (Ayer 
, Ajer 
, Eyer ) , in all the world, is a common surname. The surname Айер is habitual in Switzerland, where it is quite a common surname, Nepal, and Turkey, where it is quite a rare surname. In absolute terms, it is the most numerous in the United States, Nepal, and Turkey. Very seldom, Айер is the forename as well as the last name.