Gonna have to agree with MrZwij...When I played my first FTB map I remember looking at the recipe for the gravichestplate and my nonexistent stock of iridium and just grumbling. I did make an electric jetpack as soon as I could and then went up the lappack progression, and I remember the times (yes, more than once) that I irresponsibly equipped my lappack in a dangerous area only to forget that I didn't have the jetpack on, resulting in the loss of both
If this jetpack was available then, I would have been quite content to work up to it.
If people are worried about this jetpack auto filling tools with power, then you could always just do what I used to and unequip your jetpack to put on a lappack. If your tools are draining it too quickly, then just be cognizant of what you're doing... i.e., don't spam a mountain with your jackhammer or vajra... if that's your plan, then carry a separate lappack to equip, or keep a bag with an electric wrench / omnitool, an MFSU, and a large capacity battery pack or 2 to recharge your pack on the go. I usually play with a friend or 2 and we always have 1 shared enderpouch so that if one is at home and the other is exploring, we can just charge each other's stuff through any distance.