A big difficulty here is that the
menuExtras key in
com.apple.systemuiserver is an array that's reordered when you drag your Menu Extras around in the menu bar (and add and remove them).
In your case cited above, the Wi-Fi Menu Extra is the second item (which is array index 1 because these arrays are zero-indexed like C arrays), so you could remove it with
PlistBuddy, which isn't in your
$PATH because it's hidden in
/usr/libexec. You have to use
PlistBuddy because the
defaults command doesn't have syntax for specifying an array index. Then kill SystemUIServer to get it to reload:
/usr/libexec/PlistBuddy -c 'Delete :menuExtras:1' ~/Library/Preferences/com.apple.systemuiserver.plist
To add it back in, do something like this:
/usr/libexec/PlistBuddy -c 'Add :menuExtras:1 string "/System/Library/CoreServices/Menu Extras/AirPort.menu"' ~/Library/Preferences/com.apple.systemuiserver.plist
Note that this will break if you ever remove or add Menu Extras such that the Wi-Fi Menu Extra is not the second Menu Extra from the left in your menu bar. With a little more scripting work you could walk the
menuExtras array looking for the AirPort (Wi-Fi) menu extra, note its index, then feed that into your PlistBuddy command.