Flight Control HD

I recommend going for this trophy and "Holding Pattern" at the same time, but nevertheless they require the same principle. This will obviously be made a lot easier if you start a level out and right from the beginning, don't let any aircraft land. Personally I found it a lot easier using one of the huge maps (maps #6, #7 and #9 seem to work best) because of the extra airspace. Obviously for Holding Pattern, you only have to keep one aircraft from landing. As long as the same plane/helicopter stays airbourne for 3 minutes, you can let all the other aircraft around land if you wish (which makes things a lot easier too!). The trophy will pop after 3 minutes pass for both of these.