This achievement is for the mission Siege and can be done in the campaign or in Free mode. I personally did it in free mode on rookie to make it easier. During the mission you will have to protect SOVA 1, a large transport plane, as it tries to land, if you are successful the achievement will unlock as soon as it touches down. If it gets destroyed just hit restart checkpoint in the pause menu and it will take you to the point it starts its landing. There are 4 planes attacking as it tries to land you just need to engage and destroy them as quickly as possible. On rookie difficulty it only took me 2 attempts to get this.