Novice and experienced travelers alike need to keep up with the seemingly ever changing rules of carry on luggage. And while it is usually a good idea to check directly with the airline you will be traveling on, here are some airline carry on baggage basics:

Size Restrictions

For both domestic and international flights, your carry on bag should be no larger than 45 inches. Keep in mind that the 45-inch guideline is for the total of your luggage's length, width, and height. A standard 45 inch bag measures 22 inches by 14 inches by 9 inches, but if you have an odd shaped bag, you will be okay if the total measures at or under 45 inches.

Be careful when choosing what type of carry on baggage to purchase. For instance, not all carry on baggage is correctly marked. Some companies will measure their bags from the inside, meaning that the outside measurement is actually too big to be considered a carry on. Plus, if you have a lot to carry on, your bag make be stretched beyond the allowable limits.

Stowing Your Carry On

If you have a carry on that is close to 45 inches, it may not fit under your seat even though it is within the size limits. On some airlines you may find that there is more storage room underneath the middle seat than underneath the aisle and window seat, but this is not always the case. If you have to board with a large carry on, board your plane as soon as possible to make sure that you will have room for your carry on in the overhead bins. Of course, the best way to avoid storage problems is to travel with the smallest carry on bag that you can. This way you will be less likely to run into problems.

Carry On Allowance

Some airlines vary when it comes to the number of carry ons that they will let you take on board, but in general you are allowed one carry on bag plus one personal item. Personal items include things like a briefcase, camera, purse, laptop, backpack, a book, umbrella, or a coat.

While some airlines might not be strict when it comes to your carry on baggage, you should be aware that there have been some changes and the rules are getting tighter. Now that many airlines are charging to check a bag, many more travelers are attempting to carry on all of their baggage. In the past, an airline might let you take an additional carry on, but these changes have all but eliminated this leeway.

International Restrictions

If you are traveling domestically, you probably won't have to worry about the weight of your carry on baggage. However, some international carriers have weight restrictions as low as 11 pounds for a carry on bag. Check with your carrier before you travel so you don't have to repack any of your bags before you can check in or board your flight.

Prohibited Items

Tighter restrictions also affect what you can bring with you on your flight. For an up to date list of restricted carry on items, visit the prohibited items page of the Transportation Security Administration website.