PUBG is altering the way the plane works which should provide more chaos in the initial moments of the match but also the way air drops work for the late game.
The longer the players stay in the plane, the less manoeuvrability they will have since the altitude will be lower the further the plane goes. Should someone stay in for the whole ride, they will lose 50 per cent health immediately. Furthermore, the plane's direction and angle at which it descends will be randomised to you can't rely on it to have the same vector every round.
Overall, this change should provide more diversity in the beginning of the match since players will not have as much time and room to plan their drops. As for the late game randomisation, there is a change to the air drops.
Care packages are great but it's usually one player that takes the lion's share of the loot and the rest can just take scraps. The new changes are trying to minimise that effect by having additional air drops next to the big one. These smaller ones will not have as much loot but they will be there so no one feels entirely left out.