#!/bin/bash

ADAPTER="en0"
WIFI=`/usr/sbin/networksetup -getairportpower $ADAPTER | awk '{ print $NF }'`

if [ "$WIFI" = "On" ]
then
  `/usr/sbin/networksetup -setairportpower $ADAPTER off`
else
  `/usr/sbin/networksetup -setairportpower $ADAPTER on`
fi

Instructions

• Open up Automator
• Create a new Service
• Double-click ‘Run Shell Script’
• Select ‘no-input’ from ‘Serivce receives’
• Input the shell script above and save it
• Replace the adapter with the name of your WiFi adapter. This can be found by running ifconfig.
• System Preferences -> Keyboard -> Shortcuts
• Under ‘General’, set a Hotkey for toggling the WiFi adapter. Mine is Control + Option + Command + W.