We're elopement photographers and experience co-creators, so we get this question a lot!
The right garment bag depends on the dress (size of the skirt, if there's any beading, etc.), but this is a client favorite: https://www.amazon.com/Trifold-Garment-Breathable-Foldable-Traveling/dp/B07XF4WPQM/r[…]sprefix=wedding+dress+carry+on+garment+bag%2Caps%2C101&sr=8-5
Some things we love about it:
• trifold makes it easier to work with/carry on (less likely to be asked to check it)
• hanger holders
• internal straps
If your dress has some volume to it, we also love this one: https://www.amazon.com/AliceHouse-X-Large-Breathable-Carrying-Suitcase/dp/B01JWEHCUK/ref=sr_1_43?crid=6WVFU6DV89DD&keywords=wedding%2Bdress%2Bcarry%2Bon%2Bbag&qid=1655843759&sprefix=wedding%2Bdress%2Bcarry%2Bon%2Bbag%2Caps%2C122&sr=8-43&th=1
We also recommend contacting the airline before your flight to ask about a closet so you don't have to fold the garment bag.
Finally, we love travel-sized steamers, depending on the fabric of your dress: https://www.amazon.com/Electrolux-Handheld-Powerful-Portable-Clothing/dp/B08N5LXQ4P/[…]13011&s=home-garden&sprefix=travel+steame%2Caps%2C125&sr=1-11