Quick Answer: The Delsey Helium Aero carry-on is commonly listed at about 21 × 14.5 × 10 inches before expansion. Its height is friendly to many domestic limits, but the 14.5-inch width and 10-inch depth exceed the familiar 22 × 14 × 9-inch template used by many airlines. Whether it is accepted depends on the operating carrier, the exact measuring method, whether the expansion...