League-of-legends – Can quicksilver sash remove Airborne

Cleanse removes:

Cleanse is a 'non-targeted' summoner spell. It is mainly used to remove crowd control effects to escape or catch a target. It cannot be used while suppressed but can remove most disabling debuffs. Unlike Quicksilver Sash it reduces new debuffs after all current ones have been removed, making it a more effective escape mechanism.

However, cleanse cannot be used to remove suppression effects:

Cleanse cannot be used while suppresed, and thus can not remove spells like Warwick's Infinite Duress, Malzahar's Nether Grasp and Skarner's Impale.

Quicksilver sash (QSS) removes almost any debuff but does not have the same duration reduction afterwards that cleanse benefits from. QSS is a great buy when you are a target of suppression ultimates.

I'm not sure it's a good idea to compare them - while they do the same thing, they have very different costs.

I'd say only go Cleanse if there's dangerous CC in bot lane, and you might need the summoner spell to avoid losing early game, which Vayne is usually bad at. Otherwise, use that slot for Heal (or maybe Exhaust), again mostly for early game. Basically, you spend this summoner spell to keep you alive before you have time to farm up and get items.

Quicksilver Sash on the other hand, is a mid-late game item buy. You get this to survive in teamfights when the enemy has CC that can lock you down. Most team comps have at least some CC, and if you're playing Vayne correctly, you are probably their #1 target, so you should expect to eat all of those abilities. The question isn't really "should I get Quicksilver Sash?" but "when should I get Quicksilver Sash?". You want at least one big item (i.e. Bloodthirster, maybe Phantom Dancer) to really boost your damage, and then think about your next items. If there's a lot of enemy CC, you might pick up the Quicksilver Sash next; if you think you can survive the teamfights, you might instead buy another big damage item, and only get the Sash if the game goes long.