Task: Text to Code
Input (English): Step 1: For each row in routes table, find corresponding rows in airports table and in airlines table.
Step 2: find the number of rows of each value of airports's country in the results of step 1.
Step 3: find airlines's country of the results of step 1 with largest value in the results of step 2
Output (English): SELECT T3.country FROM routes AS T1 JOIN airports AS T2 ON T2.apid = T1.dst_apid JOIN airlines AS T3 ON T1.alid = T3.alid GROUP BY T2.country ORDER BY Count ( * ) Desc LIMIT 1