Aircrack-ng is described as '802.11 WEP and WPA-PSK keys cracking program that can recover keys once enough data packets have been captured' and is a popular app in the Security & Privacy category. There are six alternatives to Aircrack-ng for Linux, Aircrack-ng, Mac and Windows. The best alternative is Fern Wifi Cracker, which is both free and Open Source. Other great apps like Aircrack-ng are reaver (Free, Open Source), Wifite (Free, Open Source), Pyrit (Free, Open Source) and netsniff-ng (Free, Open Source).
Fern Wifi Cracker is a Wireless security auditing and attack software program written using the Python Programming Language and the Python Qt GUI library, the program is able to crack and recover WEP/WPA/WPS keys and also run other network based attacks on wireless or ethernet...
Wifite is an automated wireless attack tool. Wifite was designed for use with pentesting distributions of Linux, such as Kali Linux, Pentoo, BackBox; any Linux distributions with wireless drivers patched for injection. The current version 2 is a complete re-write of the original.
netsniff-ng is a free, performant Linux networking toolkit. The gain of performance is reached by zero-copy mechanisms, so that on packet reception and transmission the kernel does not need to copy packets from kernel space to user space and vice versa.