Crete is just a giant mess. Can't get any planes near the island if flying too low, and if the player flies too high, the parachuters get their asses rittled while falling to the ground.
Also if this game's physics actually works, the Junkers pilot can slingshot a glider by gently diving downwards and get more speed, then detaching the glider and pulling up again. That should make the glider's decent much faster.