I don't see any point to not actually using planes, the fuel explosions were real, so if the building was rigged with thermite like I'm thinking it was they likely had radio activated ignition systems daisy chained from the top and bottom. Why bother not using planes, seriously just have a few mossad guys co-opt an al-qaeda cell and get them to do it, Then make sure all possible evidence points to al-qaeda so we can get a blank check for middle eastern fuckery, the mossad team probably intercepted communications to the al-qaeda team and so al-qaeda never even had to be aware what their boys were up to and the twin towers were already one of their targets so the rag heads doing the dirty work don't even have a clue they have been co-opted.