Do these luggage sets meet major airline carry-on size limits?

The 20-inch and 21-inch carry-on pieces in this roundup are designed to fit standard U.S. domestic carry-on limits (22 x 14 x 9 in), and reviewers confirm they pass gate sizers when not over-expanded. International carriers — especially low-cost European airlines — often use smaller sizers, so reviewers caution that any expandable carry-on is risky if you fly Ryanair, Wizz, or similar with the expansion zipper open.