Sentinel 2 altitude is 786 km, which roughly translates to a velocity of 7.5km/s relative to Earth surface.
For a plane at 10 km, that means that it is displaced, roughly, one pixel each second (10m) (ignoring the plane movement, which adds more pixels, and contrails moving with the wind).
It is evident that the plane is displaced more than one pixel, so recording each band must take many seconds.
Those must be small planes, at high speed. Probably military.
That effect is common, you can see plane color ghosts on Google maps/earth.
