And do you all agree we are talking groundspeed here? I stand to be corrected...
It depends what you are interacting with.
An aircaft in flight only interacts with the air around it- so the only meaningful velocity and thus KE is relative to the air.
For an Aircraft landing on an Aircraft Carrier, the KE needed to be absorbed will be that RELATIVE to the Aircraft carrier.
Speed relative to the ground has no special significance unless one is talking about contact WITH the ground, such as landing on a runway.
KE varies as the square of velocity, but velocity is RELATIVE- the same object has different measures of KE depending on what you are measuring Velocity against.
Misunderstanding this leads to such things as the "Great Downwind Turn" myth.