At the risk of sounding like a smartarse... Get another ship?
Assuming there are shields covering the entire planet, then there's nothing you can do without the controlling group granting you access.
Even if there is NPC transport to the planet, which would allow you to bypass the shields and reach the ship, you'd then be stuck under the shield WITH the ship. Which I suspect is not helpful for you.
If the shield is only covering the square with your ship, and there are gaps, then you do know you can descend and cross terrain to it, then fly back out the same way?
I am assuming it's the ship under the shield, not you.
____________"May the Grace of Ara go with you, and His Vengeance be wrought upon your enemies."
Only fools and children dream of heroes.