Blown Out of the Sky Achievement in Halo: The Master Chief Collection

This achievement is best done in a Custom Game on Bloodline with at least one other player. There is one Hornet positioned just outside both bases at each end of the map. As for obtaining a Rocket Launcher, simply change the player traits in the Custom Game lobby so that all players spawn with Rocket Launchers.

When the match begins, one player should pilot their Hornet and fly towards the middle of the map. Here, the second player can use their Rocket Launcher to lock onto the aerial vehicle and destroy it with a single rocket. The achievement will unlock immediately after the vehicle has been destroyed, though make sure to return the favor for your partner.