A personal item backpack has to fit under the seat in front of you. The airlines that give a size allow from 9 x 10 x 17 in on United to 18 x 14 x 8 in on American, Frontier and Allegiant.
Bag type
Personal item
under the seat
Your bag against each airline
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Each airline’s personal item limit
| Airline | Personal item size | Weight |
|---|---|---|
| American Airlines | 18 x 14 x 8 in (45 x 35 x 20 cm) | Not on its page |
| Delta Air Lines | No size given | Not on its page |
| United Airlines | 9 x 10 x 17 in (22 x 25 x 43 cm) | Not on its page |
| Southwest Airlines | No size given | Not on its page |
| Alaska Airlines | No size given | Not on its page |
| JetBlue | 17 x 13 x 8 in (43.2 x 33 x 20.32 cm) | Not on its page |
| Frontier Airlines | 18 x 14 x 8 in | 35 lb |
| Allegiant Air | 8 x 14 x 18 in (20 x 35 x 45 cm) | Not on its page |
| Hawaiian Airlines | No size given | Not on its page |
| Sun Country Airlines | 17 x 13 x 9 in | Not on its page |
| Breeze Airways | 17 x 13 x 8 in | Not on its page |
| Avelo Airlines | 17 x 13 x 9 in (43 x 33 x 22 cm) | Not on its page |
Delta, Southwest, Alaska and Hawaiian give no size: the bag has to fit under the seat in front of you. Not on its page: the airline’s page gives no weight figure, which isn’t a promise that any weight is fine.
Makers’ under-seat bags
| Bag | Outside size | Capacity | Limits it fits |
|---|---|---|---|
| Peak Design Travel Backpack 20L | 18 x 11.8 x 5.7 in (46 x 30 x 14.5 cm) | 20 L | 3 of 8 |
| Peak Design Travel Backpack 20L, expanded | 18 x 11.8 x 8.4 in (46 x 30 x 21.5 cm) | 23 L | 0 of 8 |
| Away Active Convertible Backpack 25L | 17 x 13 x 7.6 in (about 43.2 x 33 x 19.3 cm) | 25 L | 7 of 8 |
| Monos Metro Backpack | 16.5 x 11.2 x 6 in (41.91 x 28.44 x 15.24 cm) | 14 L | 7 of 8 |
| Travelpro Maxlite 5 Carry-On Rolling Underseat Bag | 17.5 x 14.5 x 8.5 in (about 44.5 x 36.8 x 21.6 cm) | 26 L | 0 of 8 |
| Samsonite Upscape Spinner underseater 45cm | 45 x 36 x 20 cm (about 17.7 x 14.2 x 7.9 in) | 28 L | 0 of 8 |
| Samsonite Upscape Spinner underseater 45cm, expanded | 45 x 36 x 23 cm (about 17.7 x 14.2 x 9.1 in) | 32 L | 0 of 8 |
Each size and capacity is the maker’s own. Peak Design and Samsonite UK give an expanded size too.
Peak Design says its Travel Backpack 20L is compact enough to be your go-to personal item, and Away says its Active Convertible Backpack 25L meets most major airlines’ personal item requirements. Each still has to fit the airline you fly: Peak Design Travel Backpack 20L fits 3 of 8 of these limits, and Away Active Convertible Backpack 25L 7 of 8.
Wheels on an underseat bag
Frontier and Allegiant say their personal item size includes the wheels and handles. Travelpro’s rolling underseat bag is 15.25 x 13 x 8 in as a case and 17.5 x 14.5 x 8.5 in with its wheels and handle.