I checked a knife from Ohare through Jackson on my family's Yellowstone/Teton trip, but I didn't have a lot of faith that it wouldn't get snatched by whoever might look through the bag(s), so for that trip my trusty Ritter MK1 & MK3 got replaced by my daughter's lower cost Kabar Folding Spearpoint (still an amazing knife for just $20). It did the trick for what I needed.

I also checked the Vaseline-coated cotton balls, as I didn't want to have to explain what they were for.

Everyone in the family carried on-board daypacks w/:

<>Two 55 gallon orange trash bags
<>signal mirror
<>Storm (adults) or Windstorm (kids) whistle
<>Princeton Tec EOS headlamp w/ fresh batteries
<>Ponchos
<>Fleece jackets

In addition, I carried:

<>ACR TerraFix PLB w/ on-board GPS
<>Garmin GPSMAP 60CSx w/ City Navigator, 100K Topo, & 24K National Park Topo mapsets. I also brought a 12V power cord so that batteries were saved for when really needed.
<>Brunton 15TDCL Compass (the kids didn't bring compasses - I wanted them to stay put if lost).
<>Sparker w/ PJ-coated cotton balls (wasn't sure the sparker would get through checked security, but it did; the cotton balls were sent with checked luggage).

I should have had everyone also carry bandanas, but it didn't happen. Unfortunately the whole matches/lighter thing is so confusing with airline security that we just bought matches after we got there and stored them in a plastic bag.

Ken K.