Can the aluminium frame be taken out, and can be put back in again? I have an aluminium frame in my present pack, and if I fly to Europe and want to avoid hold charges, I remove this frame. Upon arrival, I assemble an homemade frame replica made of small-diameter plastic tubing that I bought from a B & Q, our local garden centre. I strengthen the plastic tubing with wood dowling (again from B & Q) that I push into each tube. It works very well and I've found that my plastic tube method is more comfortable on my back than my aluminium frame, as it tends to flex a little as I move.