A single cable will, most likely, not work. Instead, you will need both an A/V cable and a USB video capture device.
One type of A/V cable would be a 3.5mm TRRS to RCA. This cable connects to the A/V out port (typically the same port where you would connect headphones) on your Handycam and has three RCA connectors (yellow for video, red and white for audio).
In turn the RCA connectors from the A/V cable would connect to the USB video capture device, and another cable would be used between the device and the MacBook Air's USB port. This device would convert the analog signal coming from your Handycam into a digital format that your Mac can read.
There may also be a requirement for an app.
If you do an Internet search you should find a number of listings for such a device.