Table schema:
CREATE TABLE table_name_48 (people_on_board INTEGER, airline VARCHAR, aircraft_type VARCHAR)

Question: What is the number of people on board at Iberia Airline, with the aircraft type of lockheed l-1049g?
SQL: SELECT AVG(people_on_board) FROM table_name_48 WHERE airline = "iberia" AND aircraft_type = "lockheed l-1049g"