This cute bear is in front of the Self Check-in Counter.
I sell luggage for a living. My guests come in and ask for the largest carry-on or checked bag allowable by the major airlines all the time. They also complain they just paid a huge sum for being over in some way. It's no secret that the airlines now nickel and dime you. I give the same education ...all the time, so I thought I'd share this information (which primarily concerns major domestic airlines). Fees aren't fun, so get around the charges this way...
For checked baggage, the weight limit is 50 pounds. If your bag is heavier and you can't scramble to redistribute some weight to other bags, you will be charged an overweight baggage fee, which start at $50 and only go up from there, one-way. Remember my advice to pack less! Buy a small hand-held luggage scale and use it. And take it with you so you can weigh your suitcase before heading to the airport for the return trip, when you're weighed down by souvenirs.
It isn't common for airlines to impose weight restrictions on carry-ons (yet) and I think it would be difficult to exceed these anyway. Make sure you can lift it!
So many people haven't even heard of oversized baggage fees for checked luggage, so I have to introduce the concept. The limit is usually 62 linear inches. This linear measurement is the sum of a bag's three dimensions. Add height, width and depth together. A large suitcase is usually 29 inches tall and usually you don't have to worry about being oversized with a bag of that size. Make sure you measure a 30" or 31" suitcase or a 35" duffel to make sure the linear measurement is under the magic number of 62.
If a carry-on is oversized, then it will be checked and checked bag fees probably apply. To be okay on all major domestic airlines, the carry-on linear measurement is 45 inches. There are airlines who allow a slightly bigger carry-on, these are AirTran, JetBlue and Southwest. Usually the airlines measure just the bag, as in not including the wheels (which stick out on spinners) and handles, but they could. If they fit it into a box, then they do. When shopping for a carry-on, a 21" or 22" tall bag is the biggest you can go (21"-22"x14"x9"). (Sometimes international airlines limit a bag at 19"x13"x8".) This carry-on is to be stowed in the overhead compartment. You are also permitted a personal item, like a handbag or business case, (small enough) to be stowed underneath the seat in front of you.
Before a trip or your next purchase of luggage, log onto the websites of the airlines you frequently use for specific information. I would love to see a guest who's done their homework!
Even after I explain this, some people take offense-- how dare I suggest they limit all they want to take! Someone recently told my associate that she planned on taking ten pairs of shoes, that of these her flip flops had to match every top... They will tell you they see lots of people who get by with huge bags and that they've had a bigger bag and no problem before. Every airline and, heck, every check-in associate acts differently. I might say "I just don't want you to run into trouble later" as luggage is usually a long-term purchase, especially the quality luggage I sell! Travel is hectic enough, comply with restrictions.
There are other forms of transportation, like car, bus and train, where they aren't so strict and penalizing!