Love my longchamp bags. This one is a great size for your second carry-on. Unexpanded it fits under the seat in front. Haven’t tried it expanded under seat yet. If you always find you need an extra bit of space when you pack, get this! Gives you some wiggle room!
This is absolutely the most perfect travel bag. It fits as much as carry on luggage and looks so chic. I went on a 4 day ski trip and it easily fit all of my bulky ski clothes and toiletries. The handle is so very well made. I highly recommend this bag if you're tired of lugging around the hard suitcase as I was. Being able to fold it up nicely is just another perk!