CREATE TABLE airport (id VARCHAR(255), country VARCHAR(255), name VARCHAR(255)); CREATE TABLE flight (pilot VARCHAR(255), airport_id VARCHAR(255))
What are the different pilot names who had piloted a flight in the country 'United States' or in the airport named 'Billund Airport'?
    
SQL: SELECT DISTINCT T2.pilot FROM airport AS T1 JOIN flight AS T2 ON T1.id = T2.airport_id WHERE T1.country = 'United States' OR T1.name = 'Billund Airport'