They may be used by non-Brotherhood members of the Minutemen or the Railroad only upon completion of their respective main questlines. They can be used initally only when the player character is a member of the Brotherhood of Steel. The vertibird signal grenade can only summon a vertibird when used outside. The grenade produces a vertical plume of orange smoke. Alternatively, the player character can change the destination mid-flight using the Pip-Boy map. When the vertibird has landed, the player character may exit or use the Pip-Boy map to select a different destination.
Opening the Pip-Boy map and selecting a location to fast travel to will cause the vertibird to lift off and start flying to the selected location.
The player character can then board the aircraft to take control of its side-mounted minigun. Soon after throwing a vertibird signal grenade, a vertibird will appear on the horizon and track towards the Sole Survivor and land in the vicinity of the marked location, albeit not instantaneously.