Ask the owner to lower the shield/ If the shield generator is linked to a computer control centre, then ask to be added to the crewlist of the computer control centre. If not, you can't get past it.
[Or what Luna mentioned about landing where the shield isn't present, then cross-terraining]
How do you find the owner of the Shield Generator?
in my BR-23 freigher trying to get to the Star Port at (gov:new republic)
Sector: Unknown Regions
System: Csilla: (-301, 342)
Planet: Csilla: (6, 14)
halluraan primary spaceport
Surface positon (5,4)
but can't land as it is shielded.
So following above advice have landed at unshield
Sector: Unknown Regions
System: Csilla: (-301, 342)
Planet: Csilla: (6, 14)
City: Csaplar (7, 2)
Ground Position: (8, 11)
city Csaplar instead (old rebublic) but don't seem to have a cross terrain option/ tab under travel>planet etc & can only travel around city caspler under travel>city.