Bags That Fit the Strictest US Airlines
If you fly Frontier one month, Allegiant the next and a basic economy ticket after that, you do not want three different bags. You want one bag that passes every sizer. This guide works out the smallest size that fits all the strict airlines, using only their official limits, and explains which bag features help you get there.
The smallest bag that passes every strict airline
The short answer: a bag packed to 17 x 13 x 8 inches or less fits the personal item limit on Frontier, Allegiant, Avelo, Breeze and Sun Country. If you also fly United Basic Economy, shrink the middle side and aim for 17 x 10 x 8 inches or less.
These are packed sizes, measured at the widest point, wheels and handles included. A bag's listed size does not count if it bulges past the limit once it is full.
Personal item limits side by side
Each airline lists its sizes in a different order. Below, every limit is sorted from longest side to shortest side, in inches, so you can compare them directly.
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American and JetBlue are in the table for comparison, since many travelers on the lowest fares of the big airlines also try to travel with a personal item only.
How we worked out the common box
A bag has to pass every side on every airline. So for each side, the limit that counts is the smallest one in the group.
Step 1: the longest side. Frontier and Allegiant allow 18 inches. Avelo, Breeze and Sun Country allow 17. The smallest is 17.
Step 2: the middle side. Frontier and Allegiant allow 14 inches. Avelo, Breeze and Sun Country allow 13. The smallest is 13.
Step 3: the shortest side. Avelo and Sun Country allow 9 inches. Frontier, Allegiant and Breeze allow 8. The smallest is 8.
Result: 17 x 13 x 8 inches fits all five strict low cost airlines.
Adding United Basic Economy: United's middle side is 10 inches, so the middle drops from 13 to 10. United's longest side is 17 and its shortest is 9, which do not lower the other two sides. The common box becomes 17 x 10 x 8 inches.
Check a real bag: a soft backpack packed to 17 x 12 x 8 inches passes all five strict airlines, because 12 is under 13. On United Basic Economy it fails, because 12 minus 10 is 2 inches over on the middle side.
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Features that help a bag pass
Rather than naming brands, here are the features that matter. Any bag with these traits, packed to the common box, has a good chance at every sizer.
Soft sides over a rigid frame
A soft bag can give a little at the edges and settle into the sizer. A rigid frame cannot. If a hard bag is half an inch over, it is over. If a soft bag is half an inch over, removing one item usually fixes it.
Depth you can control: compression straps and a single main compartment
Depth is the side that fails most, and the common box allows only 8 inches. Compression straps let you pull the bag thinner after you pack. A single main compartment is easier to keep flat than several stuffed pockets. Clamshell bags that open like a suitcase make it easy to pack in flat layers.
No external wheels or bulky side pockets
Wheels, handles and outside pockets all count toward the size. Breeze says a personal item can have wheels as long as the whole item, wheels included, is within the limit (Breeze personal item). On a 17 x 13 x 8 inch box, wheels eat space you probably need for clothes. Side pockets with a water bottle add width, so drink the water or move it inside.
If you also fly basic economy on United
United's 10 inch middle side is the tightest in the table. A typical backpack is 12 or 13 inches wide, so it will fail. If United Basic Economy is part of your plans, look for a narrow bag, or a messenger style bag, that packs to 17 x 10 x 8 inches. On most United Basic Economy routes a full size carry-on is not offered (United carry-on bags), so the personal item is all you get. Our basic economy carry-on guide covers the other big airlines.
Packing a strict personal item for three days
- Lay it all out first. Two shirts, one extra pair of pants, underwear and socks for three days, a light sweater, a toiletry pouch and a charger.
- Wear the bulk. Put on your heaviest shoes, your jacket and your thickest layer.
- Roll the clothes tightly and lay them flat in the main compartment.
- Keep the toiletry pouch near the top so you can pull it out at security without unpacking.
- Fill gaps with socks and the charger rather than adding outside pockets.
- Cinch the compression straps and measure depth.
- Leave room for one airport snack inside the bag.
If the bag still feels tight after step 6, take out one shirt and plan to wear it twice. That small trade is usually what gets a strict personal item through the sizer.
Measure your own bag
The common box only helps if your packed bag is inside it. Our gate sizer guide has a five minute home test using a tape measure and masking tape. If you are not sure whether something counts as your personal item at all, see personal item or carry-on.
FAQ
- What backpack works for both Frontier and Allegiant?
- Any backpack that packs to 18 x 14 x 8 inches or less, wheels and straps included. Both airlines use the same personal item limit. If you also fly Avelo, Breeze or Sun Country, aim for 17 x 13 x 8 inches.
- Will a 30 liter backpack fit as a personal item?
- Airlines measure inches, not liters, so the volume alone cannot tell you. Measure the packed bag on all three sides and compare it with your airline's limit, such as 18 x 14 x 8 inches on Frontier.
- Is a soft bag better than a hard one for the sizer?
- Usually, yes. A soft bag can give a little and settle into the sizer, and you can remove an item to slim it down. A rigid bag that is over the limit stays over.
- Can my personal item have wheels?
- Breeze says yes, as long as the whole item, wheels included, is within the limit. Wheels always count toward the size, so on strict airlines they use up space you may need.
- Which airline has the smallest personal item size?
- United, at 17 x 10 x 9 inches, has the narrowest middle side in our table. Among the strict low cost airlines, Breeze at 17 x 13 x 8 inches is the smallest overall.
- Do they measure every bag or just the ones that look big?
- Gate agents tend to check bags that look full or bulky, and strict airlines check more often. A bag packed inside the common box and kept slim is the one least likely to draw attention.
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Disclaimer
Bag rules change. Confirm size, fee, and fare rules on the airline site before you travel. BagRule is a publisher site and does not sell tickets or bags.