I fly AC from YYZ to LAX round trip. Business class is most comfortable. Their economy seats are spacious too compared to other airlines. I'm not sure if older planes are generally more spacious tho. At the airport, I check-in early so it doesn't matter if only a few counters are open. Check-in is standard process. My issue is at the gate before boarding when the flight is full. I don't understand why they urge passengers to check-in their carry-on before boarding because the flight is full and there is limited overhead storage? Didn't they know that before hand?!!! Carry-on holds valuables, important documents or stuff one would need to keep an eye on coz check-in luggages do get lost. The receptionist at the gate urged me to check-in my carry-on. I said I have important stuff in there and I don't have a lock. The receptionist offered to seal the suitcase and assured me that it will be fine. Yah... my suitcase was sealed indeed. A huge packing tape covered the entire zipper path. I had to buy goo gone to remove the sticky goo residue all around the rubber sides of the zipper coz it was messy and dirt keeps getting stuck to it. Oh well... at least I got my hand carry back sealed and safe.