Why would you want to cut it so close? I interviewed there last year and it took around 3 hours I believe. But regardless of that I wouldn't schedule a flight that only allows me a few hours for the interview! Things happen, interviewers could be late, traffic is bad around that area.
If my interview were at 8:30 I wouldn't plan to be at the airport earlier than 2:30. I mean, that's just me but I'd play it safe. Good luck!