Horizontal Aerial Moving Speed - this measures how fast a character moves left and right in the air.

Just as a side note: Yes, Dr. Mario falls faster and farther horizontally in the air than Mario does. Test it yourself if you don't believe me. 

Note: Unlike all the other characters, Jigglypuff travels FASTER in air than on the ground while running(however, it's faster to travel by Rollout in courses like the F-Zero 1-player Adventure Mode Stage).

1) Jigglypuff
2-3) Mewtwo / Yoshi
4) Captain Falcon
5) Peach
6-7) Link / Young Link
8-9) DK / Mr. Game & Watch
10) Zelda
11) Ness
12-14) Dr. Mario / Marth / Roy
15) Samus
16) Mario
17-18) Pichu / Pikachu
19) Sheik
20) Bowser
21-22) Ganondorf / Kirby
23) Ice Climbers
24) Luigi
25-26) Falco / Fox