I am going to ask this here since our LOs are older and we have probably had more time to travel with them...we have a 2 yr old and newborn and bought a baby trend sit and stand double stroller. Has anyone ever flown with a double stroller before? I just got off the phone with american airlines and was told they do not allow you to put car seats and big strollers under with baggage when you get to the gate anymore and if the stroller was too big we would have to check it at ticketing and the carseat would have to be checked at ticketing but they would not count against us as bags. I was hoping to keep the stroller and carseat till we boarded to keep the kids manageable while we waited to board....
~Mel~

Re: anyone ever fly w/double stroller?
Everything has to fit through xray, but airlines have different rules about checking at the gate.
I usually bring two umbrella strollers because someone is always with me. or when the baby was little I used an umbrella stroller for my older daughter and the nap and go with the carseat. I buy my girls their own seats so I need their carseats.
I just flew AA and this is definitely the case... and they were strictly enforcing the rules for carry-on sizes, etc. I bought a cheap umbrella stroller before the trip and was SO glad I had it, along with my Ergo. The website even discouraged people from checking large strollers at all. I wouldn't trust those people to take care of anything nice... and you never know what will happen with your itinerary. We got stuck in that mess at DFW with the tornadoes. We were so glad to have the stroller with us (as opposed to checking it) and all of our luggage got left out in the rain when they pulled it off of the hail-damaged plane. If you have a consignment store near you, it's worth checking the umbrella stroller selection. Best $10 I've spent in a long time.
They may say this but, it's not totally true. Even my single stroller and car seat didn't fit through some of the scanners. Every airport...and even security lines at the same airport have different sized x-ray belts. If it doesn't fit, they pull it over on the side, swipe it for explosives and use the metal detector.
Personally, I will not be checking a good stroller ever again. My Chicco Deluxe Umbrella came off of a USair flight with a bent axle. I would definitely try to gate check it, if you can. Or consider renting/borrowing a stroller when you arrive at your destination.
Yeah, they can hand check car seats or strollers.