Yes you can. Although you could also check your car seat in and take your buggy with seat/cot to the plane door if that gives you more options the other end. I'd recommend bags to put the car seat/seat in to avoid getting filthy and remember that you probably won't get you buggy back til the baggage carousel so worth taking a sling as it can be a hell of a long walk carrying the baby otherwise. Also if you're taking an expensive travel system make sure your travel insurance will cover it being in the hold. Most won't and the amount the airline will pay out if they wreck it isn't much. We have a cheap buggy for travel for this reason.