I applied in-person. The process took 3 months. I interviewed at BAE Systems USA (Burlington, MA) in Jan 2019
Interview
Initial interview with two employees (one senior, one junior) at a conference job fair, then the senior employee attended my talk at that conference. This was followed by a phone interview, and finally I was then flown out for a 1-day in-person interview with multiple people in 1-hour chunks of time
Interview questions [1]
Question 1
Technical questions on algorithms & probability, non-technical questions on proposal-writing abilities