Carry-on luggage size restrictions vary by airline-here's how to tell if your suitcase, backpack, or duffle bag is small enough to bring as a carry-on.

While a well-packed carry-on can get you far, the best checked luggage provides ample packing space for long-haul trips.

Best for: a carry-on bag via Delta, United, American, JetBlue, Alaska, Southwest, and Allegiant ...