You will definitely earn this if you are going through the campaign on Veteran, or if you are playing the Competitive multiplayer scenarios. The easiest method if you don’t want to wait is to load up the Japanese Training Grounds, use the first map, and select any Kamikaze plane to launch from the airbase. Climb reasonably high and then dive at the carrier (nice big target). When you are lined up click the and hold it in, which will kick in your turbo. 600 kph is roughly 370 mph if you are using the Imperial measurements, so if you are not going fast enough when you impact try again from a higher altitude.