This is the airport. The first time we see it is in Cardcaptor Sakura: The Movie when Sakura wins a trip for four to Hong Kong! It can also be seen in two episodes when Meilin goes home and in one episode where Syaoran goes home.

Cardcaptor Sakura: The Movie
43. Sakura's Farewell to Meilin
60. Sakura and a Precious Friend
70. Sakura and Her True Feelings