Change the flags of a vehicle sub mesh in asset editor.

Flags_VehicleSubMesh.cs

var subMesh = 0; // sub mesh id, order as in ui, starting from 1 (0 is main mesh)
var asset = ToolsModifierControl.toolController.m_editPrefabInfo as VehicleInfo;

// required and forbidden flags, use | to set multiple flags
asset.m_subMeshes[subMesh].m_vehicleFlagsRequired = Vehicle.Flags.Created | Vehicle.Flags.Flying;
asset.m_subMeshes[subMesh].m_vehicleFlagsForbidden = Vehicle.Flags.Reversed;

// parked flags
asset.m_subMeshes[subMesh].m_parkedFlagsRequired = VehicleParked.Flags.CustomName;
asset.m_subMeshes[subMesh].m_parkedFlagsForbidden = VehicleParked.Flags.None;

// all vehicle flags:
/* 
	Created
	Deleted
	Spawned
	Inverted
	TransferToTarget
	TransferToSource
	Emergency1
	Emergency2
	WaitingPath
	Stopped
	Leaving
	Arriving
	Reversed
	TakingOff
	Flying
	Landing
	WaitingSpace
	WaitingCargo
	GoingBack
	WaitingTarget
	Importing
	Exporting
	Parking
	CustomName
	OnGravel
	WaitingLoading
	Congestion
	DummyTraffic
	Underground
	Transition
	InsideBuilding
	LeftHandDrive
*/

// all vehicle parked flags:
/* 
	None
	Created
	Deleted
	Updated
	Parking
	CustomName
	All
*/