One of the priorities of Dronecode is to integrate with other open source software communities, include Linux as the lower (OS) side and ROS at the applications layer. Dronecode is part of the Linux Foundation and the Open Source Robotics Foundation, which makes ROS, is part of Dronecode.
One of the things that has held ROS back from widespread adoption by drones to date is that it was originally designed for indoor robots with very reliable communications between nodes, while UAVs operate in a much less reliable communications environment. But ROS 2.0 has been designed to handle such distributed mobile robotics systems with less reliable communications links, and it can uses a sophisticated middleware layer that both handle non-deterministic communications links and restore communications links if broken.
Here's an update from the ROS community on how ROS 2.0 is coming as it prepares for release.
ROS has been an enormously important resource for the robotics community. It turned eight years old at the end of 2015, and is currently on its ninth official release. As ROS adoption has skyrocketed (especially over the past several years), OSRF, together with the community, have identified many specific areas of the operating system that need major overhauls in order to keep pace with maturing user demand. Dirk Thomas, Esteve Fernandez, and William Woodall from OSRF gave a preview at ROSCon 2015 of what to expect in ROS 2, including multi-robot systems, commercial deployments, microprocessor compatibility, real time control, and additional platform support.
The OSRF team shows off many of the exciting new ROS 2 features in this demo-heavy talk, including distributed message passing through DDS (no ROS master required), performance boosts for communications within nodes, quality of service improvements, and ways of bridging ROS 1 and ROS 2 so that you don't have to make the leap all at once. If you'd like to make the leap all at once anyway, the Alpha 1 release of ROS 2 has been available since last September, and Thomas ends the talk with a brief overview of the roadmap leading up to ROS 2's Alpha 2 release. As of April 2016, ROS 2 is on release Alpha 5 ("Epoxy"), and you can keep up-to-date on the roadmap and release schedule here.