If, according to that jet boots URL, kerosene burns at 500ml a minute then surely an equally combustible liquid such as urea would also be a viable fuel (human bladders can hold a maximum of 700-800ml!).
Would it be too much to ask for a wee powered rocket pack?
I don't mean a small Scottish one either...
EDIT:
Oooh! Daddy! Can I have one of these:
