*courtesy of pst.org
You should pay attention to this trophy to ensure you don't miss it. After finishing missions, the statistics screen will tell you if there have been casualties or MIA (Missing In Action) pilots. If one of your pilots has gone MIA, you will get the option to search for him after completing a mission. Choose "Yes" and land in various locations on the map until you find him. Locations are marked with glowing green circles and are randomised.
Note: You can also change pilot (by pressing and holding triangle ) and deliberately crash to force a pilot to go MIA.