JetOS is a real-time operating system for avionics applications. It was started as a fork of POK that is an open source ARINC-653 compliant real-time operating system. All the changes made are provided as open source software under GPLv3 license.

Since then, code has been significantly rewritten and the new operating system have got a new name: JetOS.

The key new features include:

• preemptible kernel;
• APEX services complying to ARINC-653 part 1 specification;
• IO partitions with UDP/IP networking stack and device drivers;
• gdb server supporting debugging kernel and user partitions.

JetOS supports PowerPC(Book E) and x86.