Like most weapons, rocket fire follows a normal arc when shot. However, its arc is hidden and is not traced. Rocket fire will move about semi-randomly, however it will ultimately follow the path of this hidden arc, similarly to Spaz and Wicked Witch. This hidden arc is affected by portals, black holes, wind and round bumpers. Flat bumpers and side bumpers will not change the arc's trajectory.
The further a rocket is from the hidden arc, the faster it'll try to catch up to it.
Since the hidden arc is not affected by [flat] bumpers, rocket fire can be aimed straight through bumpers to some extent, but this is not recommended. Video example provided.
The hidden arc can pass through the center of a black hole, but it can get held in there, leading all the rockets to gravitate towards the black hole further.
The visible rocket fire shot is never affected by black hole, as it always follows the hidden arc. However, it can still be swallowed by the black hole if it touches the center.
It is possible for the hidden arc to pass through portals and black holes while the visible attack never does, which result in no trick shot XP bonus.
You will only receive trick shot XP bonuses, as well as activate buffs and drones, if a rocket does a trick shot. Hidden arc is not considered.
The animation that plays when a shot goes off-screen is played for both when the hidden arc leaves the screen, as well as when a rocket leaves the screen, doubling the amount of animations played.