Here's more from the YouTube description:
A UFO was filmed by a pilot flying over Costa Rica, original video was posted to Youtube on January 30th, 2013. The silver, rounded orb flew past his airplane at an incredible rate of speed. The pilot was filming out the window with an iPhone when the silver orb whizzed past. But, he claims, he did not notice it at the time.A closeup of the saucer-like object doesn't help much to identify what it is, but it doesn't resemble any known aircraft. And it cannot be a bird as it is much too large and flying much too fast. The UFO is rounded, silvery and doesn't appear to have wings. It's not showing aviation running lights and there is no exhaust plume exiting the tail. The craft does resemble many other unidentified flying objects filmed in the area in the last few years, which is considered to be a hotspot for sightings.