Well WEP is a joke, taking approximately 5 minutes to crack any key!
As mentioned WPA is just not possible to crack unless the passphrase is a dictionary word.

This is when you turn to more imaginative methods, such as using airbase-ng in conjunction with a web server, to fake an AP and request the user's passphrase for "authentication" aka phishing. Not easily implemented on a mobile device let alone a desktop terminal.

The inherent weakness of WPA/WPA2 is that people set passwords that are "easy to remember" or that are relatively short in length. Each time you extend your passphrase by one character you theoretically multiply the previous number of possible combinations by 94!