This carrier worked perfectly for flying my 14-year old, 16-pound Westie from San Diego to Milwaukee (and back) during the Thanksgiving holiday. We flew US Airways and despite the large size being slightly bigger than required dimensions, we had zero problems whatsoever. Here are a few answers to questions I had before flying that may help ease your concerns: 1. US Air did not check that he could stand up or turn around 2. It was tight, but he could, in fact, stand up and turn around 3. US Air did not check any health certificates- all I had to do each way was sign a short form that the person at the counter filled out on my behalf. Although I was very nervous about getting turned away due to the size of the carrier, I acted like we had done this a million times (unlike the woman in line next to me with a dog that did not stop barking/squealing for the entire 15 min I was next to her). We both had a large Sherpa carrier and we both got through. 4. The strap is extremely sturdy and my dog felt comfortable with me holding him through the airport 5. I brought a blanket with me to cover the carrier in case it didn't fit completely under the seat. The carrier DID fit with a little squishing and maneuvering, but since the flight atttendants on some of the flights were very strict, I used it to be able to pull the carrier out from under the seat mid-flight and give my little guy some reassuring pats on the head. The blanket was also helpful when my late night flight had all the lights on- I wanted my dog to sleep and be relaxed, so I covered the holes. When it got very warm mid-flight, I threw him a few ice cubes to rehydrate. 6. TRAINING: To get my Westie ready for his first flight, I bought the carrier about 2 weeks before. The first day or two, I motioned with treats and he walked in himself. I left the top open so he wouldn't feel claustrophobic. Once he was comfortable with the "box" (as we called it), I started closing the front door and placing him in the top hole (again, always with treats). I didn't let him walk out on his own after this part of the training; I wanted him to know that once he was in his box, he couldn't leave without me taking him out. Once he became comfortable sitting in the box, I put a treat on the bottom and as soon as he put his head down to get it, I zipped the lid and let him enjoy his treat in there. I expected him to freak out the first time (my dog is not well-trained by any means; he will not even sit on command most days), but he stayed calm, so after about 5 minutes of me sitting by his box, I picked it up, did a few laps around the apartment, went down the elevator, loaded him up in the car and took a short drive to the pet store. He didn't mind at all. After I saw that, we toned down the training to every couple of days. Some nights after work, I would put him in his box (always through the top and always with a treat before the lid was closed) and put him at my feet while I watched TV for an hour or two. I would never walk away from the box and occasionally gave him reassuring pats or words of encouragement every 30 mins or so. Due to time constraints, we never trained for staying in the box longer than 2 hours, despite us having about a 7 hour trip time with the layovers. A few training tips: buy soft treats and use VERY tiny pieces. Especially at the beginning, you will likely be going through quite a few treats, so the smaller, the better. You don't want your dog throwing up in there (or expecting large treats on the plane!) Also, never give in to your dog if he/she tries to bite its way out of the bag. Stop the behavior and do not let it out of the carrier until the behavior has stopped and some time has passed. This is not fun to deal with mid-flight, so stop the behavior before you get in the air. 7. To help with his ears popping, I brought several nylabones on the plane (the pocket on the carrier is perfect for a few treats, a collapsible water bowl, a potty pad for layovers if you don't have time to take your dog out between flights, and a Kindle for yourself). During takeoff, I handed him a bone (I put PB on them so he would lick and bite) as I pet him. He's used to car rides, so this didn't phase him much. 8. Every so often throughout the flight, I would unzip a tiny hole (he did want to escape, so I had to be careful) and give him a small piece of treat to check on him. 9. The mesh on this carrier is STURDY. My dog has a bite similar to a pitbull, and the determination of a 6 year old trying to reach a giant piece of candy that was put just out of reach, so when he started trying to eat his way out of the carrier during the last 30 mins of the flight, every scenario of him running through the aisles like a mad man started running through my head. Luckily, however, the mesh held up and we landed safely shortly thereafter. I was left with a bruised hand due to the struggle, but the bag was just fine. 10. Day of flight: check in with plenty of time to spare. This is not the time to add stress. Once your bags are checked in and your dog has the "ok" to fly, check out the security line. If it's short, I recommend walking out of the airport and giving your dog some last-minute fresh air, one last bathroom stop, and a moment for the vet-recommended Benadryl to kick in. When the time comes to go through security, you'll put the carrier through (I also had a backpack with the blanket tied to it and a large coat) and carry your dog through the x-ray machine. I put my dog back in the carrier at this point, but if your dog's leash is easily accessible, you could probably get away with walking it on its leash to the gate (at least that seemed to be the case at SAN, PHX & MKE). You'll want to be one of the last to board (you won't have luggage, so carry on space won't be a concern). If you have a layover, check out potty areas ahead of time. Few airports have potty areas behind security (SAN is one), so you'll need to know what your options are and if you'll have time. During our short layover, I had planned to take my dog to the bathroom stall and lay out a potty pad. Since he had just gone about 90 min prior however, we spent our 20 mins between flights with his head poking out of the carrier while he observed the craziness of Thanksgiving travel. If I could do this again, I would have taken him on a quick walk in the airport to burn off some energy. All in all, flying with my Westie was much less stressful for him than boarding. The large Sherpa was great and I would highly recommend it. The only thing I would change would be adding mesh on the top of the carrier, but not a big deal.