Are you looking to go with the Arena Stubby Jet Pack? or the Regular jet pack? Because depending on which one you decide, there is a lot of reference or not a lot of reference.
The stub is a more simple design, but doesn't have any tutorials or blueprints available.
The regular pack with the rocket on top does however. Here are some threads that you may find helpful if you go that route:
Update on Scratch from WoF's plans
A member using WizardOfFlight's templates
Jet Pack Draft Blueprints
WizardOfFlight's templates thread
Official Lisa Fett's Jet Pack Tutorial
LisaFett's jet pack tutorial
Keep in mind, those are all for a boba fett jet pack.
But they are basically the same jet pack, boba fett's is just weathered and has a slightly different color scheme
Boba Maker is also working on a jet pack project and his site would be a could frame of reference for how he is goign about it.
My advice is to use the WizardOfFlight blueprints and use found objects, styrene, and foamboard to construct it.
I am a little over 25% done with my jet pack going on this method and the scale is dead on. Take your time, this is important. Save caps, empty bottles, paper tower rolls, cups, tubes, lids etc. etc. etc.
Being an art student I know the important of found objects sitting for months before finally beign the perfect fit for something, but trust me, it'll turn out a whole lot better if you wait and have everything to scale.
Some recogmendations so far with how i've done it,
Thrusters: Air fresherners, the ones you lift a bit to release the scent, are great for the thrusters, the top cap i mean.
Middle Rocket tube, an oatmeal can. The one i got was a quaker and matched the circumference of the circle on wizardofflights bp's perfectly.
Just take your time, cut out those templates and keep an eye out for things with a familiar shape.
good luck
-=QuinN!