eeex
eeex
eeex
xxxx

e = elevated terrain
x = squares adjacent to the elevated terrain

In a game I was playing in last night, a character stopped in x, soared, and then dropped the character in e. Is that legal? I was just wondering since the rulebook doesn't specifically cover a taxi like this.

Soaring is not the same elevation as elevated terrain. A figure carrying another figure cannot end its movement in soaring, because there is nowhere adjacent to drop the carried figure. Squares labeled "e" and "x" on your diagram are not considered adjacent to each other either (they're at different elevations), so it wouldn't be valid for a flier who is on one elevation to drop its carried figure in another elevation.

LeaLu is 100% correct, and here's the reference from the Icons Rule book to back it up (so you can show it to your friend, if you like).

Icons Rule Book (page 18 and 19):
when a carrying character ends its movement, the carried character must be placed in a square adjacent to the carrying character that the carried character can occupy. A carrying character must end its movement so that the carried character can be placed in a square the carried character can occupy.

And from page 17:
Soaring. A soaring character is flying high above the battlefield. To show that a character is soaring, move the flight indicator on its clear center post to its highest position, as shown in Figure 6. Soaring characters ignore the effects of all types of terrain and objects on movement. Soaring characters can affect only other soaring characters, giant characters, and big characters.

So even if a soaring figure is next to a piece of terrain, it is not really adjacent to that terrain since soaring figures ignore all terrain and objects. A soaring figure is at a different elevation than the terrain.

I knew that the squares themselves were at two different elevations and therefore were not adjacent. When he orignially tried to do it I told him he couldn't do it because the squares weren't adjacent and then someone said if he soared that he could drop him on that square. You're response makes sense, however. Thanks for the help!