What to Look For in a Travel Backpack (From a Brand That Made One)

Choosing the right travel backpack can make or break a trip. Whether you’re navigating busy airports, hopping between trains, or exploring a new city, your backpack is more than just a bag – it’s your mobile home base. A poorly designed bag can leave you with aching shoulders, repacking headaches, and regrets at every gate. A great one? It feels effortless, like it was designed for the way you actually move through the world. But with endless options on the market, it can be overwhelming to know what really matters.

In this guide, we’ll break down the essential features to look for in a carry-on backpack, from comfort and capacity to design details that make life on the go smoother. We know this because we’ve lived it. After years of traveling with backpacks that were never quite right, we finally designed the perfect one ourselves. We’ll share an insider perspective on what actually works in the real world from years of trial and error, not just what sounds good on a product page.

By the end, you’ll know exactly which factors are worth prioritising. You’ll also learn how to spot the difference between a pack that’s just okay and one that will become your most trusted travel companion. Here’s what we learned about what really matters when you’re choosing a backpack for travel.

1. Comfort & Fit

If you’re carrying your pack for hours, comfort isn’t negotiable. Look for a travel backpack with these features:

• Supportive shoulder straps that are padded without being bulky. Contoured and padded straps distribute weight more evenly across your shoulders.
• A breathable back panel to prevent overheating. A padded back panel with airflow channels or mesh lining prevents overheating and reduces that sweaty back feeling. Even when dashing across the airport, the Flow 40L Travel Backpack's back panel combines breathable Airmesh padding with a central ventilation channel to keep you comfortable.
• Adjustable sternum straps to spread weight evenly and help keep the shoulder straps from sliding outwards. This feature stabilises the load, especially when you’re moving quickly.
• Ergonomic shaping. A good carry-on backpack places the heaviest main compartment closest to your back, so the bulk of the load stays near your body’s centre of gravity, while outer sections hold lighter items like your laptop, chargers, and small essentials. By distributing weight this way, the backpack feels lighter on your shoulders and doesn’t pull you backward. It’s a small detail that makes a big difference on long travel days.

These details may sound small, but together they make the difference between a backpack you can carry comfortably for 20 minutes versus one you’re happy to wear all day, even when it’s fully loaded. The fit should feel natural – like the backpack is part of you, not something you’re constantly adjusting.  The Flow 40L Travel Backpack does all this, bringing every comfort detail together in a design built to feel balanced, supportive, and easy to carry.

2. Capacity & Size

Your backpack should balance space with portability. The sweet spot for most carry-on travellers is 35-45L – roomy enough for clothes, toiletries, tech, and essentials, while still fitting easily into overhead bins and adapting to trips of any destination or duration. 

• Too small and you’ll be cramming things in or forced to add a second bag.
• Too large and you’ll lose the ease of carry-on travel due to your backpack being overweight or over-sized.

A structured interior with thoughtful compartments helps maximise every litre. The best packs encourage you to pack light but smart. The Flow 40L Travel Backpack is intentionally minimal on compartments, giving you the freedom to pack in the way that suits you best without being restricted by over-engineered layouts. Its suitcase-style design maximises usable space and makes it easy to pair with packing cubes or other organisation tools.

Weight matters too. An empty pack that’s too heavy eats into your carry-on allowance. At just 1.06kg, the Flow 40L Travel Backpack is lightweight enough to keep you within limits while still feeling sturdy. Every detail has been designed with intention; instead of layering on a dozen extra features that only add bulk, the Flow 40L Travel Backpack keeps things streamlined so every gram works hard for you.

If you’re unsure about what airlines actually allow, check out our detailed Airline carry-on size guidelines.

3. Durability & Materials

Your travel backpack will be tested by real-world conditions: rain, crowded luggage bins, and the general wear and tear of being dragged around the world. That’s why materials and build quality matter just as much as style.

What is denier?

Backpack materials are often referenced by their denier (D), a measure of the thickness of the individual threads used to weave the fabric. In simple terms, denier gives you a quick read on how tough, heavy, or lightweight a material will be.

• Lower denier counts (e.g. 210D, 300D): lighter, more flexible fabrics, often used for linings or internal compartments.
• Higher denier counts (e.g. 600D, 900D): denser, more abrasion-resistant fabrics, ideal for the outer shell and high-wear zones.

Many backpacks only use lightweight polyester in the 200–300D range, which feels fine in a store but quickly frays, tears, or loses its shape after a few trips. The best backpacks use a mix of deniers: heavy-duty fabrics where durability matters most, and lighter ones where flexibility and weight savings improve comfort. That’s why the Flow 40L Travel Backpack pairs ultra-durable 900D on the outside with a lightweight 210D lining inside – tough where it counts, light where it matters.

Its outer shell combines 900D RPET – dense, abrasion-resistant fabric that shields against scuffs and rough handling as well as being water-resistant – with 420D RPET ripstop panels that reinforce high-wear zones like the base and mid-body. Ripstop is a special weave where thicker reinforcement threads are interwoven at regular intervals, creating a subtle grid pattern. This design prevents small tears from spreading, which is why it’s used in outdoor gear built to last. See how ripstop works here.

Inside, a 210D RPET lining keeps things lightweight but structured. A 210D lining strikes the right balance of being durable enough to resist abrasion from packing cubes, laptops, and chargers, but thin and flexible enough to keep the overall bag light and easy to carry.

The padded RPET Airmesh back panel completes the design, adding breathability and cushioning for long travel days. 

Learn more about denier here. 

What is RPET?

RPET stands for recycled polyethylene terephthalate, a durable polyester fabric created by transforming used plastic (like bottles and packaging) into new fibres. It offers the same strength and performance as traditional polyester, but with a significantly lower environmental footprint since it reduces plastic waste and cuts down on energy use in production (read more about RPET and sustainability here). The Flow 40L Travel Backpack uses RPET for all outer fabrication including the shoulder straps and back panel, as well as the lining.

With this in mind, always consider a backpack made from recycled materials. You’ll get durability and peace of mind knowing your bag is kinder to the planet.

Hardware and stitching

Hardware is equally important. The Flow 40L Travel Backpack uses premium hardware:

• Duraflex® buckles that built to last without cracking under pressure, and
• SBS® lockable zippers that ensure smooth closure and won’t snag or break when the bag is fully packed.
  

Reinforced stitching on all straps and handles is essential to ensure your carry-on backpack can withstand years of lifting, carrying, and travel strain.

4. Ease of Packing

Traditional top-loading backpacks force you to dig around endlessly. The Flow 40L Travel Backpack was intentionally designed to open like a suitcase, so you can see and access everything without unpacking your life on the airport floor.

Features to look for that make packing easier:

• Suitcase-style clamshell opening that zips all the way around. 
• Internal mesh compartment, just like in a suitcase, to keep items separated and visible. 
• Packing cube compatibility to help you pack smarter and stay organised. The Flow 40L Travel Backpack’s dimensions are purpose-built to fit our Large Packing Cube, Small Packing Cube, and Toiletries Bag for a total packing solution.
• Padded laptop pocket to ensure your device is protected. We intentionally positioned the laptop pocked on the front of the Flow 40L Travel Backpack, away from your spine for comfort and easier access during airport security checks. 
• Quick-access pockets for essentials like your passport, boarding passes, and chargers.
• Internal and external compression straps to tighten the load, keep belongings in place, and pull weight closer to your centre of gravity for a more stable carry.

Packing should feel organised, not chaotic. When your backpack works with you, every stage of travel feels easier.

5. Style & Versatility

Your backpack is part of your everyday travel experience. It goes with you everywhere – through airports, into cafés, hotels, and even on work trips. Choosing one that’s sleek and modern means it blends seamlessly into different settings, instead of feeling bulky or out of place.

Neutral tones like black, navy, or charcoal not only pair easily with anything you wear, but also are better at hiding scuffs and marks from the road. A clean, minimalist design keeps things timeless, so your backpack feels just as right on a city break as it does on a long-haul flight.

6. Security Features

Travel often means crowded spaces where pickpockets thrive. Smart security features in a carry-on backpack include:

• Lockable zippers to secure the entire backpack, ideal when leaving your backpack in places like a hostel or overhead compartment with peace of mind.  
• Hidden compartments for passports, wallets, or other valuables. 
• Compression straps with secure buckles that stabilise your load and make it harder for opportunistic thieves to access your bag. 
• Discreet, low-profile design that avoids drawing attention, helping you blend in while you travel.

Peace of mind is priceless. The right security details can save you from major headaches on the road.

7. Sustainability & Responsibility

Today, choosing a travel backpack is also about choosing your values. Look for brands using recycled or responsibly sourced materials, fair labor practices, and long-lasting designs that avoid fast-fashion waste.

When a bag is built to last, you buy less, waste less, and travel more responsibly. Learn more about how we approach sustainability across design and materials on our Sustainability page.

8. Price & Value

Yes, you can find a backpack for under $100 but it likely won’t last. Think of your backpack as an investment: the cost per trip drops every year it serves you well. A well-designed bag can last for a decade of adventures, making it one of the most valuable purchases in your travel kit.

Our perspective: why we made a travel backpack

After years of carrying bags that didn’t quite work, we created the Flow 40L Travel Backpack. It had to tick every box we’ve just covered: carry-on size, water-resistant recycled materials, suitcase-style opening, padded straps, and a clean, versatile design. Most importantly, it had to feel effortless to use, because a backpack should make your journey smoother, not more complicated.

The bottom line

When you’re choosing a travel backpack, focus on comfort, capacity, durability, ease of packing, and style. Then layer in features like security and sustainability to suit your personal priorities. The right one will become more than just luggage, it will be your trusted travel partner through every trip.

If you find one that feels like it was made for you, don’t let it go. Because once you experience the freedom of a truly great carry-on backpack, you’ll wonder how you ever travelled without it.