If you do a search online there's lots of bags in all prices ranges to choose from, there's a basic red plastic bag that says GATE CHECK you can get thru Babies R Us and other retailers online or you can get as fancy as a wheeled bag for $40+. We have run thru 2 bags now for car seat travel the first one was trashed by the 2nd flight it took. The one we're using now has made it longer it hasn't been as abused, but I wouldn't ever send it bagless it's just too flithy under the plane. We have one by Sunshine Kids I think it was about $20 and has a strap to carry it by, i love it. I check our older son's car seat thru in it, since it doesn't weigh 50lbs and is free to take regardless of how many suitcases you check i strap extra things into the car seat-seat. They stay secure and I get a freebie suitcase.