WestJet is by far better to fly with when you have kids. They are amazing and try to help out whenever they can. They'll hold your kids, get you anything you need, whatever, consider it done! And they don't care what kind of stroller you bring. I took my Chaperone travel system and it wasn't an issue in the least.
AC doesn't seem to know whats going on, are rude and won't let you bring more than a convenience/umbrella stroller. When we went to NS 2 summers ago, the flight attendant we had was sooooo rude. She freaked out when I passed my DD to my MIL to hold so I could run to the washroom. My SIL had my nephew on her knee in the same row, so with my DD on MIL's knee, it was 5 people in the row and the flight attendant was freaking out about masks. But, she wouldn't hold my DD either...whadaya want me to do? Its 2 minutes! After I finally got to go to the washroom and got my DD settled (MIL thought red eye with 4 kids was a great idea...SIL and I 100% disagree!!!), the same attendant walked by and cracked my kid in the head! She was a skinny little thing that had no reason to bump into us in the least.
The only issue I've run into with carseats on a plane is if its not a direct flight, they don't want you to use it. I don't get that, but I'm sure I could absolutely fight it. And, its sooo much easier to fly with your kids strapped in! And, they can see out the window
Just a word of advice...ya, I forgot to flip the buckle when I flew the one time...the fight attendant had to remove the seatbelt from the seat to get my carseat free
Remember to flip so the belt release is facing the plane seat back...lol!