“This is a really good size for a travel backpack. It was large enough to fit a ton of items. It expands, but it’s still small enough to fit under a plane seat and on top of carry-on luggage ...

When it comes to air travel, choosing the right backpack is almost as important as booking the right flight. But with so many options on the market, how do you find the perfect travel backpack?

Anna Popp is a New York-based associate editor at Travel + Leisure, covering all of the best travel products, from luggage to outdoor gear. She has been a travel writer, editor, and product tester ...