Seeking "personal item" bags

Ones you can fit under the seat in front of you

I’m not the world’s best planner, unless the thing I’m planning is a trip that requires air travel, and then I’m capable of going down some serious logistical rabbit holes. We’re headed to L.A. for six days pretty soon, and I want to bring carry-on luggage, and this decision requires near-military precision, because the older I get, the tougher it gets …