The key difference between DevOps in the context of Avionics and, aircraft/spacecraft merely has to do with deployment velocity due to FAA certifications, Aircraft re-grooms and the way in which the Airline industry releases their changes.
But ultimately, DevOps is not exclusive to High Velocity delivery methods (like Agile). And can be done in the context of Waterfall methods or other similar methods.
In some ways, the airline industry is often factory oriented, which aligns well with Kim, Behr, and Spaford's depiction and conceptualization of DevOps.
Development on LRUs and racks can easily be done using an Agile methodology using a DevOps mentality. These many small changes can be stored up and released periodically to undergo final rack testing and certifications (such as AS9100). Airlines could be doing much more to leverage automation for software deployment to fleets and have yet to capitalize on these developments.
At the Avionics company I worked for for several years, we were seeing several successes and challenges with implementing DevOps. I simply can't emphasize enough however that challenges were internal and political, not technical or methodological challenges. These are also not systematic issues resulting from industry regulations, policies and standards. Avionics companies who are able to innovate and provide better value, higher reliability and cheaper costs will easily be able to out-innovate their competitors and gain traction and market share. The Avionics industry is ripe for this kind of shakeup and DevOps is well suited to be a cause of changes.