Flying to NYC for a Superday from Philadelphia

Book a flight, they are literally paying

Amtrak is literally faster than a flight bro. Amtrak if I remember correctly from philly is like 1-2 hours depending on Acela/ the slow one and takes you to Penn station in Midtown and a short walk to all the offices you mentioned. A flight would probably be 5+ hours between getting there early and ubering from whatever airport into Manhattan. 

Amtrak is a train, not a bus. It's also significantly faster for that distance. I would recommend giving yourself some wiggle room, but to be honest, the Northeast Corridor line rarely is off-schedule.

Amtrak is very reliable (high-speed train), give yourself some room in case of major delays but you should be fine.

With a 10am interview I would also consider getting there the night before and stay in a cheap hotel, even taking the earliest train I wouldn't risk it for an interview