What are your airline travel packing hacks?

[CarlyeThornton]

When packing for a trip, getting everything in can be such a challenge. I typically find rolling my clothes and utilizing shoe space to be a good strategies, especially since I can be pretty indecisive about my wardrobe for vacations. It also helps that Southwest lets two bags fly free! 
 
What are your best packing tips and tricks? 

[plusmommy]

Knowing I can always check two bags (thanks, Southwest), I often travel with one bag but pack an empty duffle back. This way, depending on where I'm going, I can pick up souvenirs without worrying my bag might become overweight or too stuffed.

Then, I always travel with my carry-on backpack, which has a small bag that fits in the seatback pocket while I'm fying. This tiny bag contains gum, snacks, a book, and a charger - so I have all the essentials I need within reach!

[tappingmom1]

I always pack one of those very small, foldable, nylon grocery-type bags in my carry-on.  If the need arises that my carry-on needs to be gated checked, I can easily move valuables (electronics, medication, sunglasses, jewelry, etc.) into the nylon bag for under seat storage.

[SoCalFlyer97]

For most of my day-trippers and one-nighters, with a little help of rolling up my clothing, I can get everything packed into a standard school-sized backpack. For my multi-day trips that require more clothing, I roll with the 50L Carofield backpack duffle (about20x13x8). This piece came complete with packing cubes and a separate compartment for the laptop that allowed me to make the most of the space. I roll the clothes up and pack 'em in the cubes.

Also, I place the 311 bag, laptop/electronics, and any other 'unusuals' in an easily accessible area in case TSA ever needed to look at it.

One key benefit of this Carofield backpack...If there's no overhead bin space next to a vacant window seat, this bag (believe it or not) does fit under the seat in front of me, even toward the front of the plane where the total width is slightly narrower. Also works for middle seat, but not for the aisle seat.

This basically allows me to pick any open window seat regardless of how full the overhead bins are. Plus, a side benefit is I can have access to the bag during all phases of the flight anytime above the 10k' mark regardless of whether the seatbelt light is on.