Agile in a safety critical environment...
I have no problem with the AirBus FCS being developed in an Agile manner. However I do have a real problem with it being TESTED in an Agile manner.
Agile Smagile!!!! It's all a pile of old bollocks, and there is no right or wrong answer when you are actually out there at the coalface actually delivering stuff rather than sitting in a controlled environment such as a lecture theatre or a home office cracking out Agile whitepapers. The foundations required for delivering large successful projects haven't changed in over 20 - 30 years and most experienced managers will pick and choose which method suits the project best based on several learned criteria.
In summary - I find a mix of both Waterfall and Agile works best for larger projects and programmes. WAgile perhaps?