Airtool is a system menu-bar application that provides basic functions to check the state and channel configuration of the built-in Wi-Fi adapter, as well as to perform frame captures on single and multiple channels. It can be used together with Wireshark to let you change channel settings while performing live frame captures. In addition, captures can be automatically uploaded to CloudShark.
Note: While the software is classified as free, it is actually donationware. Please consider making a donation to help support development.