Using "Virtual PC" software on a Macintosh?
We started out using a G3 with Virtual PC and did indeed use Airmail and the Winlink system for almost a year that way. Airmail (and Sailmail) are relatively undemanding programs and are not impeded by the emulation software. The catch is a special cable to connect to the Mac from the TNC; Jim Corenman has notes on that in one of his help files, as I recall.
We ended up moving to PCs. You may be like us and only have a few applications in mind when you start out...but that seems to change over time. And sadly, there is far less of (nautical) value available for the Mac. Moreover, if you begin assembling a pack of friends while sailing, you will all find custom applications, solutions to common problems, a tide program or utility that sounds wonderful...but which you can''t use.
We were using our first Apple in 1984; we had to accept PCs at work but never thought we''d leave the Mac family on our own buck. Truth be told, PCs are far easier (and more Mac like) than they used to be, and my wife (THE Mac fan in the family) no longer notices much of a difference. Just food for thought...