The middle column displays the contents of the selected category, and the far right panel holds the selected message body. The far left contains boxes and categories that you can use to sort your messages for easier retrieval later on. Nice interface: When you open this app, you'll see three main panels that make up the basic organizational structure of the program. You can receive, view, compose, and send messages, all through this program's intuitive interface. Airmail for Mac is an alternative to the Apple Mail app that allows you to link all of your email accounts, so you can keep everything organized and in one place.