Okay so according to "Indian sources" (which are world-renowned for egoistic bullshit).
These "choppers" managed to miraculously evade the most militarized border, sneak past an advanced network of air defenses, pass through several alerted patrolling squadrons armed with hi-tier radars, get completely ignored by one of Pakistan's largest aerial exercises, fly over layers of man-pad squads, undetected by radars dotted throughout the region, - then land on one of the most mountainous regions (that too being undetected by hundreds of patrols) and then repeat all that to get back to the right side of the border. They managed to be soo stealthy that no one in Azad Kashmir heard or saw of this.
I'm sorry, but this can only happen in Bollywood - not reality.
This story was just a cookie given to the angry public to appease them and increase their false-ego.