Quite right, the ships can be at any angle and the flames will look the same, I also used this in the Galaxy menu for the hyperspace routes, I slightly cheated by using EZ Rotate :p, but it's faster than anything DBP could do, here's the function I use:
Function RollPlainTo( ObjID )
EzRo_SetEuler OAX ( ObjID ) , OAY ( ObjID ) , OAZ ( ObjID )
EzRo_SetPos OPX ( ObjID ) , OPY ( ObjID ) , OPZ ( ObjID )
EzRo_LX 90
Ang# = EzRo_FindLocalYAngleToPoint( CPX () , CPY () , CPZ () )
EzRo_LX -90
EzRo_LZ Ang#
EzRo_FindEuler
Rotate Object ObjID , EzRo_GetEulerX() , EzRo_GetEulerY() , EzRo_GetEulerZ()
EndFunction
Note: The CPX/Y/Z, OAX/Y/Z are constants for Camera Position, and Object Angle(I hate typing the full thing out every 2 mins :p).