Here's something I've often wondered. What is the typical ground distance covered that an airliner will travel to get from FL0 (ground level) to crusing altitude-say FL320 (32,000 feet)? Is it 40 miles? 50 miles? 75 miles? 100 miles? What about in reverse, on descent? How much ground distance will be covered starting with descent to zero AGL? I realize that there are certain variables involved, such as payload, a/c type, and whether or not the distance travelled is a straight line. But let's make it easy, and take a straight flight path.

Put another way, picture a triangle. The hypoteneuse is the flight path. Line X is altitude, from zero to 35,000 feet. Line Y is the ground distance. The intersection of the hypoteneuse and line X is FL350, level flight. The intersection of the hypoteneuse and line Y is the runway, and touchdown.

What is the typical distance of line Y?