So basically different airport have to unlock different planes right?

Yes, here is the list:
INN - AT76
BRI - B462
PRG - E190

Other airports don’t have planes that you can unlock for free.

After you unlock each time then, you have that in your fleet or only once.

After that, you don’t have to use silver planes or golden planes to unlock them anymore. You still have to buy them with money, though

The B34F in LEJ

Uh no?