Is the salary received from working at the airport unlawful, knowing that part of the airport's income comes from rents of shops that sell alcohol and cigarettes? And is facilitating procedures for tourists who do not adhere to Sharia considered cooperation in sin?

There is no objection to your salary as long as you work in what is permissible. The presence of shops selling prohibited goods at the airport does not affect it, as the airport management's money is mixed, and it is permissible to deal with mixed money. Furthermore, there is no objection to your work in facilitating the entry procedures for tourists, as this transaction is originally permissible. If they commit what Allah has forbidden, there is no sin upon the employee because of it.