Airmail has a bunch of shortcuts available in the menu title. If you’re feeling uncomfortable with the current shortcuts, there is a way available to remap them. In the following screenshot you can see that its shown in 'System Preferences > Keyboard > Keyboard Shortcuts':
1. Choose a menu title you wished to Remap
2. Enter your desired shortcuts for Airmail.
Once you have re-mapped the keyboard shortcuts, you can use the new shortcuts in Airmail.
Please note that the use of a third-party shortcut mapper can cause serious issues with keyboard shortcuts in Airmail.