As nouns the difference between courier and airmail
is that
courier is a person who looks after and guides tourists while
airmail is the system of conveying mail using aircraft.
As verbs the difference between courier and airmail
is that
courier is to deliver by courier while
airmail is to send mail by air.
As a proper noun Courier
is a monospace font that resembles the characters produced by a typewriter.
As an adjective airmail is
of, or relating to such a system.