Knockback can be cleansed by QSS

Airborne effects like knock-backs can't be cleansed in any way :D? Yeah you thought till now :P Tried with a friend to cleanse the knock-back from Vaynes E with QSS - and it worked O.o

From the Wiki http://leagueoflegends.wikia.com/wiki/Crowd_control

Airborne: A unit that is airborne is unable to control its movement, attack or cast abilities for the duration. The duration is also unaffected by crowd control reduction and cannot be removed by cleansing effects.

Airborne crowd control effects are made up of two components: a movement modifier (called a "move block" by Riot, referring to a chunk of code) and a stun (which is responsible for the disabling to attacking and casting). In the game, the most recent move block will over-rule any previous move blocks.

Move block: The duration is unaffected by crowd control reduction. The effect cannot be removed by cleanse effects.

ACTIVE: Vayne fires a heavy bolt at the target unit, dealing physical damage, Airborne icon knocking them back and applying Silver Bolts.png Silver Bolts. Phrase knocking them back is linked with Airborne.