PX4 PRO is a software middleware for autonomous systems and robots used to build a wide variety of drones. According to its official documentation:

PX4 can fly anything from a racing to a cargo drone - be it a multi copter, plane or VTOL.

Installing PX4

Connect your Erle-Brain2 to internet, open one terminal and execute the following commands:

sudo apt-get update
sudo apt-get install px4-erle-robotics

Uninstalling PX4

Open a terminal and type the following:

sudo apt-get purge -y px4-erle-robotics

PX4 official link.

Note: Before install PX4 package please uninstall other apm package. Please, be careful with PX4, for the moment is beta.