[HYPOCRACY]

The drag must be enormous at low level altitude. Physics says no. I think. Lol.

[Navy Patriot]

The drag must be enormous at low level altitude. Physics says no. I think.

OK, now you're asking questions that requrire more detailed answers.

Generally speaking, yes, lower altitude = more drag, however vehicle shape has a lot to do with it.

Ramjets operate better at higher speeds and can adjust air intake to their advantage at higher altitudes.

BUT very low altitudes, speed and maneuverability make missiles hard to intercept.

So designers "adapt" Physics to the task by vehicle shape, guidance surface shape, Resonance created by specific speed and, if necessary, air intake size and shape.

Now you need to sort this info into very specific areas of missile technology because not everything fits everything.

For instance, Pulse jets operate at different resonances (the pulse) depending on speed and atmospheric temperature and density, and the high tech engines can adjust, whereas the V-1 engine could not adjust, it was fixed.