First of all, understanding the airfoil(aerofoil) shape can not cover up the whole physics of an aeroplane.There are many physics and also chemical theories to keep an aeroplane fly.To summerise, your introduction to aviation is not exactly correct.For example, we don't use flaps or slats just to slow down in landing.We use it so that in a slow condition,we can keep the aircraft fly and "not stall it" or "bang it into the ground".And it's not like the aircraft itself stops climbing altitudes when reached a desired altitude.The pilots has to put effort to fly that aircraft what we call "straight & level".That part is , in fact,the second most difficult jobs in flying ,after landing phase.Pilots don't simply control the aircraft to fly.They use all 5 senses,"taste,touch,smell,sight,hearing" to fly with the help of understanding almost all the flight physics , human factors, weather, and at last ,aircraft itself.Just a comment, you know.. we, pilots don't usually tolerate such things..we talks