Originally Posted by Superguy
IIRC, a chem professor said in class once that hydrogen peroxide can generally only get to a 30% concentration before it starts getting really unstable. It is VERY difficult to have a higher concentration without more extreme methods of containment.
Not only is H2O2 above 30% very unstable, but TATP itself is less stable than nitroglycerine and is much more hazardous to make. Would-be terrorists trying to make some in the lav with a bucket of ice, high-concentrations of acetone and peroxide, and a touch of sulfuric acid would be much more likely to blow the stuff up prematurely, which would only main / kill them as the process would be incomplete.
I also just don't know how realistic terrorists making TATP aboard a plane would be (same for nitroglycerine, really). For so many explosives, it's critical to hold the temperature at the right level during nitration so that esterization proceeds at a reasonable rate--too low and the explosive is fairly useless, and too high and it explosively decomposes before completion.