Can You Bring a Backpack and Carry-On? Complete TSA & Airline Rules

One of the most confusing aspects of air travel is understanding what counts as a "personal item" versus a "carry-on bag." Can you bring both a backpack and a rolling suitcase? The answer is usually yes, but the rules are more complex than most travelers realize.

The Simple Answer

Yes, you can typically bring both a backpack and a carry-on bag on most airlines. However, your backpack must qualify as a "personal item" and fit under the seat in front of you, not in the overhead bin.

Understanding the Two-Bag System

Carry-On Bag (Overhead Bin)

Purpose: Primary luggage storage
Size: Varies by airline (typically 22" x 14" x 9")
Location: Overhead compartment
Examples: Rolling suitcase, large duffel bag, large backpack

Personal Item (Under Seat)

Purpose: Items you need during flight
Size: Must fit under seat (typically 18" x 14" x 8")
Location: Under the seat in front of you
Examples: Small backpack, purse, laptop bag, small duffel

Personal Item Size Limits by Airline

Major US Airlines

American Airlines

Size: 18" x 14" x 8" (45 x 35 x 20 cm)
Must fit under seat
Examples: Small backpack, purse, briefcase

Delta Air Lines

Size: Must fit under seat (no specific dimensions)
General guideline: Smaller than carry-on
Examples: Laptop bag, small backpack, purse

United Airlines

Size: 17" x 10" x 9" (43 x 25 x 22 cm)
Must fit completely under seat
Examples: Small backpack, laptop bag, purse

Southwest Airlines

Size: 18.5" x 8.5" x 13.5" (47 x 21 x 34 cm)
Must fit under seat
Examples: Small backpack, laptop bag, camera bag

Budget Airlines (Stricter Rules)

Spirit Airlines

Size: 18" x 14" x 8" (45 x 35 x 20 cm)
Strictly enforced
Fee: $65+ if oversized

Frontier Airlines

Size: 18" x 14" x 8" (45 x 35 x 20 cm)
Weight: Must be under 35 lbs
Fee: $99+ if oversized

What Qualifies as a Personal Item?

Always Allowed

Small backpack (under size limits)
Laptop bag
Purse or handbag
Camera bag
Diaper bag (when traveling with infant)
Medical equipment bag

Usually Allowed

Small duffel bag
Messenger bag
Briefcase
Small shopping bag

Not Allowed as Personal Items

Large hiking backpacks
Oversized tote bags
Duty-free shopping bags (unless they fit size requirements)
Musical instruments (unless very small)

Strategic Packing: Maximizing Your Two Bags

Backpack Strategy (Personal Item)

What to pack:

Electronics (laptop, tablet, phone chargers)
Important documents
Medications
Entertainment items
Snacks
Change of clothes for emergencies

Pro tips:

Choose a backpack that's exactly at the size limit
Use compression cubes to maximize space
Pack heavy items in your backpack to save weight in carry-on

Carry-On Strategy (Overhead Bin)

What to pack:

Clothing for your trip
Shoes
Toiletries (following 3-1-1 rule)
Souvenirs on return trip
Less essential electronics

Common Mistakes to Avoid

1. Oversized "Personal Items"

Problem: Bringing a large backpack and calling it a personal item Solution: Measure your backpack and ensure it fits size requirements

2. Double Dipping

Problem: Putting your "personal item" in the overhead bin Solution: Personal items must go under the seat, period

3. Ignoring Weight Limits

Problem: Some airlines have weight limits for personal items Solution: Check specific airline policies before packing

4. Gate Surprises

Problem: Not knowing that gate agents can measure bags Solution: Pack within size limits, don't try to "sneak by"

Airline-Specific Strategies

American Airlines

Best combo: 21" rolling carry-on + 18" backpack
Pro tip: They're stricter about size than other majors

Delta

Best combo: 22" rolling carry-on + laptop backpack
Pro tip: More flexible on personal item enforcement

Southwest

Best combo: 24" rolling carry-on + 18" backpack
Pro tip: Most generous size allowances

Spirit/Frontier

Best combo: Pre-paid carry-on + strict size personal item
Pro tip: Measure everything - they will charge fees

Special Situations

Business Travel

Best setup: Rolling carry-on + laptop backpack Why: Professional appearance, easy airport navigation

Adventure Travel

Best setup: Large hiking backpack as carry-on + small daypack as personal item Why: Versatility for various activities

Family Travel

Best setup: Large carry-on with family items + parent's backpack with kid essentials Why: Quick access to snacks, entertainment, diapers

International Travel

Best setup: Hard-shell carry-on + document backpack Why: Protection for souvenirs, easy access to travel documents

TSA Considerations

Security Screening

Both bags must go through security
Electronics larger than phone must be removed from bags
Liquids must follow 3-1-1 rule regardless of which bag

Prohibited Items

Check TSA.gov for current list, but common restrictions:

Sharp objects
Large liquids
Flammable items
Weapons of any kind

Pro Tips for Success

1. Test Your Setup

Practice packing both bags and walking through an airport to ensure comfort.

2. Keep Receipts

If questioned about bag size, having purchase receipts can help prove compliance.

3. Board Early

Earlier boarding groups get better overhead bin space for your carry-on.

4. Pack Smart

Put heaviest items in your personal item since it stays with you.

5. Have a Backup Plan

Know what you'd remove if forced to consolidate bags.

When Rules Change

Full Flights

On oversold flights, airlines may:

Require smaller bags as personal items
Force larger personal items to be checked
Offer compensation for voluntary checking

Equipment Changes

Smaller aircraft may have:

Reduced overhead bin space
Stricter size enforcement
Gate checking requirements

Bottom Line

You can almost always bring both a backpack and a carry-on, but success depends on:

Following size rules for personal items
Choosing the right backpack (under 18" typically)
Packing strategically for easy access
Knowing your airline's specific policies

The key is treating them as two distinct categories: your carry-on goes overhead, your backpack goes under the seat. Stick to this rule, follow size guidelines, and you'll never have problems.

Quick reference: If your backpack fits in the space under an airplane seat (about the size of a medium school backpack), you're probably fine. If it's hiking-pack sized, it needs to be your carry-on, not your personal item.

Airline policies change frequently. Always verify current rules on airline websites before travel. Last updated June 2025.