Translation:The airport is very close to the station.
The de doesn't bear any meaning in this construction. Its only purpose is to turn the adverb cerca into a preposition so it can be used with a noun. Most adverbs use de to be made into a preposition.
The English "to" doesn't have its usual English meaning either. "To" usually refers to a movement towards the goal, but "being close to something" doesn't involve any movement.
Those are two entirely different words. Está is the él/ella form of the verb estar, meaning "he/she/it is (in some location)".
- Él está en el jardín. - He is in the garden.
Esta is the feminine form of este, meaning "this".
- Tengo esta carta para ti. - I have this letter for you.