The project is called Partners in the Sky and is the brainchild of Smithsonian Conservation Biology Institute's scientist, Peter Marra. He's currently creating a lightweight tracking device of only .15 of a gram which can be used for all creatures large and small. It's supported by VHF radio technology to transmit data of the animal up to the plane.
Some of the greatest news comes with the ability to track previously untraceable species too small to wear larger GPS devices. Think monarch butterflies and American Wood Thrushes; they can now be included in studies to slow their disappearance and the eventual extinction. So, as you sit back, relax and enjoy your flight, you can relax a bit more in the knowledge that your trip might be doing more good than just getting you to your destination on time.
Right now the technology is still being finalized, but United has already committed to joining the project.