Any length · Everything in the cabin, nothing in the hold
One Bag Only
One-bag travel is a discipline rather than a trip length. The rule is simple: whatever you are bringing goes in the cabin, and nothing goes in the hold. People do it for a weekend and people do it for a month.
It concentrates all six tests onto one object. There is no second bag to absorb the overflow, no checked case to hide the heavy things in, and no way to fail one test and pass on the strength of another.
It is also the style of travel where the word approved appears most often and helps least, because it is the style that lives or dies at a gate frame.
What people take
Drawn from what the categories on this site are actually for, not from a survey.
- A travel pack, usually in the 26 L to 40 L range, which is where both of the travel packs here sit.
- A cabin case at the small end, chosen on trade size, most often 20 in.
- A compression organizer set, because with one bag the volume argument finally matters more than the weight argument.
- Very little else, which is the entire point.
Categories that fit this trip
- Backpacks & Travel Packsweight on your back instead of in your hand
- Packing Organizersvolume, which is not the same as weight
Where it lets you down
The same bag, the same six tests, in a different order of importance.
- Stage 3The Gate Sizer
A full pack bulges, and a frame measures the bulge. A pack sold at a stated capacity has no stated external size at all, so there is nothing to check before you are standing in front of it.
- Stage 2The Front Door
One bag means all the weight is on one strap system, and no backpack listing on this site states what the empty pack weighs.
What this trip punishes
Every trip shape has a habit it is unkind to. These are the ones this shape finds.
- Using the expansion. A pack that expands by six liters is deeper than the pack that was described as a personal item, and depth is what runs out first.
- Trusting personal-item language. Footwell space differs by carrier, by seat and by aircraft, and no listing can know which seat you are in.
- Packing to the stated capacity. A capacity figure is the volume of an empty open bag, not the volume of a bag that still zips.
- Choosing on liters alone. Forty liters in a tall column and forty liters in a flat box behave completely differently at a frame.
Worth being careful about
- Airplane approved and airline approved are marketing phrases. No carrier issues an approval in advance.
- We print no carrier size limits. Read the one your carrier publishes for your fare and aircraft.
- Compression reduces the space a load takes up and not its weight.
- Lithium power banks travel in the cabin. The FAA and your carrier publish the rules.
A stated size is the size of the body. Wheels, feet and an extended telescoping handle are not usually counted inside it, and the frame at a gate counts all of them.
Sources
The short version
One Bag Only
One bag makes the gate frame and the front door into the same question asked twice. Measure the packed bag across its widest points and weigh it, because between them those two numbers decide the whole trip and neither is on any listing.