Just curious as I saw a movie of one on TV I'm trying to understand how a cruise missile can fly? I can understand action v reaction in a rocket pushing against the mass of the earth I can understand winged flight and air pressure holding the craft up I can inderstand a hovercraft using air pressure or a helicopter generating upthrust but I dont see how you can make an object fly long distances without the upthrust of an engine or wings. My guess is they have to be permanently in a controlled fall ? Would that make sense? If so what is the thrust pushing against? And if so how would you calculate how to make such an object fly?