Travelling by air

Do I check in here for Air Canada to Mexico? You already have your ticket? Yes. Here you are. Thank you. Can you put your luggage up here, please? Sure, I have three suitcases. We allow only two pieces. You'll have to pay an extra charge. Oh! Can I carry this one with me? No, I'm sorry. It won't fit under your seat. That's $45. Here you are. Thank you. You can choose your seat. A window seat or aisle seat? I'd like a window seat, please. Fine. Seat 15A. Here's your ticket and your boarding pass. Enjoy your flight!