If the Air Flow app freezes, troubleshoot by force quitting Air Flow:
Open “Activity Monitor” on your computer
Click on the Finder icon in the Dock to open a new Finder window.
Go to the Applications section of the hard drive.
Open the Utilities folder within the Applications section.
Double-click on the Activity Monitor icon to open the utility.
Search for “Air”
Highlight the row that says “Air” and the row that says 'Air Flow' (look for the app icon.)
Click the “X” and then click “Force quit”
Restart Air