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. The player character can then board the aircraft to take control of its side-mounted minigun. 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. When the vertibird has landed, the player character may exit or use the Pip-Boy map to select a different destination. Alternatively, the player character can change the destination mid flight. The vertibird signal grenade can only be used outside, and only by members of the Brotherhood of Steel, the Minutemen or the Railroad upon completion of the former's main questline. The grenade produces orange smoke.
If the Sole Survivor completed the Railroad's main quest line, Drummer Boy in Railroad HQ after some time will say that the vertibird is ready for use, gives the Sole Survivor 3 signal grenades then informs the player character that more of them can be purchased from Tinker Tom.
- The Minutemen have two similar support items: flares and smoke grenades. The flare will signal for troops and the smoke grenades direct a strike from nearby artillery.
- The Institute has synth relay grenades to spawn synths.
First given by Elder Maxson as a reward for the quest Show No Mercy. More can be bought from Proctor Teagan aboard the Prydwen or from Tinker Tom at the Railroad HQ after finishing the main questline for the Railroad. Another way to obtain this is by completing the Minutemen questline, and upon destroying the Prydwen the player character will be given the grenade by Preston Garvey.
- The vertibird will still come even if one defeated the BoS in the main quest. However, factions such as the Minutemen and the Institute may be hostile.
- Temporary followers from BoS radiant quests, such as scribes and squires, won't use the vertibird.
- Shooting creatures in the Glowing Sea while on board of a vertibird may result in these creatures chasing the vertibird. radscorpions and mole rats may then burst from the ground upon landing.
- Throwing the grenade at an NPC (such as a settler) will cause them to become hostile.
- Signal grenades do not work on Far Harbor island or in Nuka-World.
- If the fast travel target to an area is cluttered or would be impossible to get to, the vertibird can land either time at a different area, ranging from 60+ feet to an entire cell.