Talk:Summer 2015 Event/@comment-26119700-20150811052209/@comment-25389202-20150811052907

As far as I can tell, the markings/tags simply serve as a ranking or "level" of the specific plane. Higher the level, better the stats (i.e. power or contact rate). Planes will raise in rank as you use them in combat. When shot down completely, planes lose some (if not all, not sure here) of their ranking.

Taken from http://kancolle.wikia.com/wiki/Thread:295211 :

"New Mechanics
 * New Aircraft Skill System
 * Planes (Torpedo Bomber, Dive Bomber, Fighter, different kind of Recon, etc.) will bear marking that the amount of marking would increase according to increase of their trained skill.
 * Plane squadron with high skill system provide higher power and more reconnaissance(i.e. contact rate)
 * Plane Skill would increase as they repeatedly sortie, but losing some of those plane during battle would result in decrease in their skill and if the plane squardon is completely wiped then its status would reset back to original. Note that their performance won't drop below their initial value."