I applied in-person. The process took 3 weeks. I interviewed at SpaceX
Interview
I met a few structures team and components team guys from the company when they visited my university. I talked to two of them, mostly about my previous experience. Then I had a one-hour phone interview with 2 engineers. They were very friendly and answered all my questions. The questions were almost exclusively technical - some based on my past projects and some random ones to see how you think.