No it is not. It is absurd, though I hope you are being tongue in cheek with this. And thermite would have been even more impossible than the Usual explosives. You need a crew of roughly four hundred for WTC 1 and 2 and half that four WTC 7 the so called smoking gun. Double that for thermite. In either case your talking people using concrete drills to drill through to set the charges. That's the standard proceedure and unless you wish to take extraordianry risks you don't bring the HE on the scene until after you've drilled the holes in which it is to be placed. On top of which you won't be able to use electronic ignition to detonate your charges because there are just too many cell phones around, so you'll also need miles of detwire which no one saw.