Here's a little more info on "aircheck" from this web site: http://www.oldradio.com/current/bc_1sts.htm
... AIRCHECK
* According to some reports, the oldest existing aircheck dates to the Armistice Day broadcast, November 10, 1923. * Some WEAF broadcasts of the NY Philharmonic are said to predate that slightly.
What is the genesis of the term "aircheck" and how did it come to mean "off-air recording", or did it mean something different at another time?
-- Tom Fine