-- Database schema
| airport : id [ INT ] primary_key , City [ TEXT ] , Country [ TEXT ] , IATA [ TEXT ] , ICAO [ TEXT ] , name [ TEXT ] | operate_company : id [ INT ] primary_key , name [ TEXT ] , Type [ TEXT ] , Principal_activities [ TEXT ] , Incorporated_in [ TEXT ] , Group_Equity_Shareholding [ INT ] | flight : id [ INT ] primary_key , Vehicle_Flight_number [ TEXT ] , Date [ TEXT ] , Pilot [ TEXT ] , Velocity [ INT ] , Altitude [ INT ] , airport_id [ INT ] flight.airport_id = airport.id , company_id [ INT ] flight.company_id = operate_company.id |
-- -- What are the different pilot names who had piloted a flight in the country 'United States' or in the airport named 'Billund Airport'?

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';