Jump packs and jetpacks are separate categories in 6th ed. so don't lump them together.
However, they share the rule 'Skyborne' which you need to read before going on about the movement phase. It states when you use jetpacks, you ignore all models and terrains when moving through them and take dangerous terrain tests if you begin or end your movement in difficult terrain.
That is what moving like normal infantry and activating the jetpacks mean. Nothing is stated it can move up to 12" like how the rules in jump packs are worded.