Welcome aboard! If you are running version 1.3 of the game, downed pilots will be marked by a small red smoke cloud on the water when you are nearby. Your crew won't report this, so you will have to head to the bridge and look for yourself when you arrive near a location marked on the map. Also keep in mind that the pilots drift with the ocean current, so they won't be near the original position report as time passes. That means you should head to a position soon after it is reported to have the best chance of finding the pilot.
After you locate one, just head towards him and use the binocular view (not the TBT) and highlight the guy with the crosshair. When it turns red, hit the "rescue pilot" button in the menu bar and you should be good to go. Repeat as necessary to complete mission.
Hope this helps!
