Airline Carry

One of the most stressful parts of flying can be the packing process, especially if you're trying to fit your items into one or two carry-on bags.

Regardless of whether you are flying a U.S. carrier or internationally, your flying with both a full-sized carry-on and personal item depends on the policy of the specific carrier. We've outlined many of those policies in this guide. Additionally, all airlines have size requirements, and some have weight restrictions.

Read on for all you need to know about traveling with carry-on bags.

As you've likely observed, most domestic airlines allow passengers one personal item that fits underneath the seat in front of them and one larger carry-on suitable for the overhead bin.

Some airlines specify size requirements for both items, while others only restrict the overhead baggage. Just remember that a carrier's policy for the larger carry-on accounts for the size of your entire bag, including your luggage's handles and wheels.

The standard size requirements across the board for most domestic airlines for your larger carry-on is around 22 by 14 by 9 inches, so that's a good rule of thumb to keep in mind.

Here are the carry-on policies broken down by U.S. airlines:

Carry-on items stored overhead must be 24 by 16 by 10 inches. Personal items for under the seat – including purses, briefcases, cameras, food containers, laptops and backpacks — cannot be larger than 16 1/4 by 13 1/2 by 8 inches.

The combined length, width and height of carry-on baggage should be less than 45 inches. Individual items must be less than 22 by 14 by 9 inches.

American Airlines passengers should heed the 18 by 14 by 8-inch limit for personal items and 22 by 14 by 9 inches (including handles and wheels) for overhead items, which also must fit in the sizer at the gate.

All under-seat personal items on United must measure within 9 by 10 by 17 inches, while larger items cannot exceed 22 by 14 by 9 inches, including handles and wheels.

Similar to the other domestic carriers on this list, JetBlue says that personal items must measure less than 17 by 13 by 8 inches, handles and wheels included, while overhead items shall be smaller than 22 by 14 by 9 inches.

Alaska Airlines recently changed their carry-on bag size limit for overhead items to be within 22 by 14 by 9 inches, including the wheels and handles.

Carry-on items aboard Hawaiian Airlines flights cannot exceed 22 by 14 by 9 inches.

The standard carry-on size for international carriers is slightly smaller than that of the U.S., measuring overall at 21.7 by 15.7 by 9 inches, including handles and wheels.

Here are the carry-on policies for economy passengers on major international carriers:

Read more: Your essential guide to duty-free shopping at the airport

As mentioned, all airlines differentiate between smaller personal items and larger carry-on items. If your carry-on bag fits under the seat in front of you, it's considered a personal item, which includes small backpacks, purses, briefcases and laptop bags.

Larger bags, including suitcases that fit in the overhead bin compartment, are labeled as larger carry-on items.

Most domestic airlines allow passengers two carry-on items, depending on their fare type. For example, Southwest stands out among carriers for allowing passengers two free carry-on bags and two checked bags, regardless of fare type. That's also the case for Delta, American, Alaska and Hawaiian passengers.

The cheapest fare types on both United (basic economy) and JetBlue (Blue Basic) restrict fliers to one personal item that can fit under the seat in front of you.

Among international carriers, your fare type also determines whether you are eligible to bring one or two carry-on items, so be sure to pay attention to baggage allotments when booking.

For carry-on guidelines for specific airlines, see our guide for the current carry-on baggage policies for 10 major U.S. and international carriers.

Though airlines care about size, most domestic airlines do not have weight restrictions for carry-on bags, but some enforce weight limits for specific routes. For example, Delta restricts passengers flying to and from Beijing and Shanghai to a 22-pound carry-on, while bags are limited to 15 pounds to and from Singapore.

Low-cost airlines Frontier and Sun Country both have 35-pound limits, while Hawaiian Airlines limits their carry-on bags to 25 pounds.

Otherwise, you won't likely find a blanket weight policy for carry-on bags for domestic carriers.

Just make sure your bag does not weigh too much that it becomes oversized.

On the other hand, the majority of international carriers specify weight requirements for carry-on bags dependent on the fare type. For economy fares, carry-on weight limits vary among major carriers, including:

The U.S. Transportation and Security Administration (TSA) monitors carry-on bags just as they do with checked luggage, prohibiting certain items, including firearms, lithium batteries and other potentially hazardous items outlined here.

Within those confines, you're further restricted to liquids less than 3.4 ounces per their 3-1-1 rule, limiting items like toothpaste, shampoo, conditioner, mouthwash and lotion to 3.4 fluid ounces within a quart-sized bag. TSA recommends you pack full-sized liquids in your checked luggage.

In addition to liquids, your carry-on is the safest place for your most valuable items, such as your purse, electronics, passport, jewelry and medicines.

For inbound international flights to the U.S., you can carry on liquids exceeding 3.4 ounces if purchased duty-free and remain in their secure, tamper-evident bags. You'll also want to hold on to your original receipt to show the purchase was made within the preceding 48 hours, which TSA may request for screening.

Other international border agencies have similar rules prohibiting bringing certain items on airplanes, so be sure to check with your individual airline regarding those rules.

Depending on your fare type, most domestic airlines generally permit travelers to carry on two items — one that fits underneath the seat in front of you, generally labeled as a personal item, and a second item that fits overhead. However, you must meet certain dimension thresholds, which vary by airline.

Personal items include small backpacks, purses, briefcases and laptop bags, while larger bags, including suitcases that lie fit in the overhead bin compartment, are labeled as larger carry-on items.

Carry-on policies greatly vary by international carriers, depending on the fare type, which also determines weight requirements for carry-on bags. However, U.S. airlines generally do not have weight restrictions for carry-on items.

Related: Here's what to pack in a carry-on bag every time you travel