Database: flight_company
Question: 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'