I interviewed at GD in early 2017. Total time was 2 months. 6 weeks for phone screen and another 2-1/2 for onsite.
HR emailed me to be there an hour before the time he told everyone else so I ended up sitting in the lobby for as long as I was interviewed. It wasn't a total waste as I witnessed an argument between somebody that worked there and a vendor rep. I was speechless and wanted to leave.
Interview was mixed and disjointed. Some really good behavioral and technical Q&A from some individuals on the 4 person panel. Alone they are were intelligent, friendly and professional. Put together the under current of combativeness, blame shifting, office politics and one-upmanship was obvious.
With all the contradictions I was confused and couldn't tell exactly who I'd be reporting to or what I'd be doing other than fire fighting between groups. Given what I saw the whole facility is probably like this and in dire need of some leadership and a reorg.
Sadly, after later talking to others that interviewed or previously worked there, my experience is very common. Also found out they filled the position with an internal transfer and had to go through the motions with fake interviews. That's certainly what the whole long, awkward and unprofessional process felt like.
Advice: Figure out who you are and where you're going before wasting people's time. For an organization that prides itself on perfectionism I saw everything but.