You fly out with one airline, everything goes smoothly, and your carry-on fits just fine. On the way back, you’re with a different airline—and suddenly that same bag becomes a problem. It doesn’t meet the size limit, and now you’re stuck checking it at the gate.

This happens a lot when switching between airlines like American Airlines and Southwest. Both allow carry-on baggage, but their luggage dimensions and flexibility are not the same.

Let’s compare American Airlines vs Southwest Airlines carry-on size so you know exactly what to expect before you pack.

American Airlines vs Southwest Airlines Carry-On Size

Feature	American Airlines	Southwest Airlines
Carry-on size	56 x 36 x 23 cm	61 x 41 x 25 cm
	22 x 14 x 9 in	24 x 16 x 10 in
Personal item	Yes (1 item)	Yes (1 item)
Weight limit	Not specified	Not specified
Carry-on included	Yes	Yes
Strictness level	Moderate	Moderate

Based on official airline policies

American Airlines vs Southwest Airlines Carry-On Size Comparison

This is where the biggest difference stands out immediately.

American Airlines

American Airlines allows:

• 56 x 36 x 23 cm (22 x 14 x 9 inches)

This is a standard carry-on luggage size used by many U.S. carriers. It works well for most cabin-sized suitcases but doesn’t leave much room for oversized or expandable bags.

Southwest Airlines

Southwest Airlines allows:

• 61 x 41 x 25 cm (24 x 16 x 10 inches)

That’s significantly larger in all dimensions.

Key Difference

Southwest Airlines is slightly more flexible because it allows a noticeably bigger carry-on size.

Even a few extra centimeters can matter when:

• Your suitcase is fully packed
• You’re using expandable luggage
• You prefer a slightly larger cabin bag

Practical warning:
A bag accepted on Southwest may be rejected on American Airlines due to tighter size restrictions.

Personal Item Rules Compared

Both airlines allow one personal item, but the approach differs.

American Airlines

• Personal item size: 45 x 35 x 20 cm (18 x 14 x 8 inches)
• Must fit under the seat
• Examples: purse, laptop bag, small backpack

Southwest Airlines

• Personal item allowed
• No exact size specified
• Must fit under the seat

What This Means

American Airlines gives clear limits, while Southwest allows more flexibility.

Example:

• A slim backpack → accepted on both
• A larger travel backpack → more likely accepted on Southwest

If your bag looks too big, either airline may treat it as a carry-on instead of a personal item.

Weight Limits & Baggage Allowance

Both airlines follow a similar approach.

American Airlines

• No official weight limit
• You must handle your bag yourself

Southwest Airlines

• No published weight restriction
• Same expectation: self-handling

Key Insight

This is common for U.S. airlines.

Unlike many international carriers:

• Weight limits are rarely enforced
• Size restrictions matter more

If you’re connecting to an international flight, expect stricter rules.

Carry-On Fees Comparison

Here’s where both airlines are fairly straightforward.

American Airlines

• 1 carry-on + 1 personal item included
• No charge for standard cabin baggage

Southwest Airlines

• 1 carry-on + 1 personal item included
• No additional cost

Key Difference

Both airlines include carry-on, so there’s no major difference in cost here.

Southwest is known for simpler policies, while American may vary slightly depending on fare type in edge cases.

Which Airline Is More Strict?

This is where real-world behavior matters more than written rules.

American Airlines

• Uses sizer bins at some airports
• Staff may check bags if they look oversized
• More structured enforcement

Southwest Airlines

• Less focus on measuring bags
• Faster boarding style
• More relaxed approach

Verdict on Strictness

Based on traveler experience:

• American Airlines is stricter in real-world enforcement
• Southwest is more relaxed unless the bag is clearly oversized

This difference becomes more obvious on crowded flights.

Real Travel Scenarios

Let’s look at how this plays out in real situations.

Scenario 1: Same Bag on Both Airlines

You use a slightly larger carry-on:

• Works on Southwest
• May not meet American’s size limit

Even a small difference in dimensions can affect acceptance.

Scenario 2: Backpack vs Suitcase

You carry:

• Cabin suitcase + backpack

On American Airlines:

• Backpack must fit within personal item size

On Southwest:

• More flexibility with backpack size

If it looks bulky, it may count as a carry-on.

Scenario 3: Connecting Flights

You fly:

• Southwest → American Airlines

Your bag:

• Accepted on Southwest
• Exceeds American’s size restrictions

Warning:
Always follow the stricter airline when packing.

Which Airline Is Better for Carry-On?

Let’s break it down clearly.

Best for Flexibility: Southwest Airlines

Southwest allows larger luggage dimensions, making packing easier.

Best for Structured Rules: American Airlines

Clear size limits help you know exactly what’s allowed.

Best for Budget Travelers: Tie

Both include carry-on baggage in standard fares.

Best Overall

Southwest Airlines wins due to its larger carry-on allowance and more relaxed enforcement.

Related Airline Rules

• American Airlines carry-on size guide
• Southwest Airlines carry-on rules
• Carry-on vs personal item explained
• Carry-on weight limits guide

Traveler Insight (Not Official Policy)

From experience, Southwest feels more forgiving at the gate. Staff usually focus on keeping boarding moving rather than measuring every bag. As long as your luggage fits in cabin storage without causing issues, you’re fine.

American Airlines tends to be more structured. At certain airports, you’ll see passengers asked to use sizer bins, especially if their bags look close to the size limit.

Another thing that stands out is how full flights affect enforcement. On American Airlines, overhead bins fill quickly, and gate checks become more common. Southwest’s open seating system spreads passengers out, which often leaves more room for bags.

FAQs

Which airline allows bigger carry-on?

Southwest Airlines allows a larger carry-on size than American Airlines.

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Can I use the same bag on both airlines?

Yes, but it should meet American Airlines’ smaller size limit to be safe.

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What happens if my bag is oversized?

You may need to check it at the gate, and additional charges may apply.

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Do both airlines allow personal item?

Yes, both allow one personal item.

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Are carry-ons included in fare?

Yes, both airlines include carry-on baggage in standard fares.

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Final Verdict

Data verified from official airline baggage policies.

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If you want a stress-free experience across both airlines, stick to American’s smaller size limit. But if you’re flying Southwest, you’ll get more room to pack—and fewer chances of your bag being questioned at the gate.