Video: It's always fun to melt your brain from what looks like the laws of physics breaking. Therefore, it's always fun to see a pilot pour water up into a cup while upside down in a fighter jet. It's something we've seen plenty before, but this view is especially cool. You get to see the entire process happen so clearly: The pilot pours the water while the plane twists around, the pilot drinks the water while it flips around and then he holds the cup of water out for good measure and doesn't miss a single drop as the plane goes upside down. It's a neat effect! And there's no magic behind it. Wired explained it quite well:
If you could just see the water from a stationary reference frame (maybe a floating hot air balloon), you would see the water indeed falling down. Now, I remember that I said "falling down" and not "moving down". The water actually might be moving up. The key is that even though it is moving up, it is accelerating down. The plane also is accelerating down. As long as the downward acceleration of the plane is greater than the water, the water will move into the cup above it.
If you want an even more detailed break down, head there for it.