I applied online in October of my senior year. I had a phone interview with an engineer that featured typical STAR type questions, and he invited me to a superday event 2 weeks later (early November). The event started with a cocktail hour the night before with about 100 other candidates, where the HR manager made a point of stating that we were not in competition with each other- there were positions available for everyone. The actual superday involved 3 interviews with various groups (hot section, cold section, defense), and was extremely laid back- they seemed more interested in what the best fit would be than whether or not I'd be up to the job. I would recommend researching the different sections as I wasn't prepared with an idea of what I would prefer. I was expecting technical questions about how a jet engine worked, but didn't receive any. The person with whom I had the original phone interview called me that night to extend a verbal offer. The P&W employees who attended superday were all extremely nice, laid back, and happy to share what they loved about their jobs, which is what ultimately made me decide to work there.
The food at the superday event was extremely spread out- we had small breakfast sandwiches at 6:30 and didn't eat again until 2:00, so I was glad I packed a granola bar.
What was extremely stressful and chaotic was dealing with the outside HR company P&W hired to organize the superday event. They wouldn't return calls to confirm I would indeed be attending the event, and didn't contact me to arrange travel until the evening before I was due to fly out for the interview. While I was on the plane, they emailed to tell me that the initial instructions to book a hotel and rental car were incorrect, and I was to call and cancel those reservations, but it was past the 24hr hotel cancellation window.