What does air-typing mean?

air-typing meaning in Urban Dictionary

The ability to type semi-coherently in thin air, as you were using the full QWERTY keyboard. Computer system geeks usually can try this with near 100% reliability, and it is generally computer geeks who can be proud of to be able to do such a feat. Utilizes the original tenses of "typing" (air-type, air-typed, air-typer, etc.)