[TACIXAT]

I was thinking recently that kites could make great signaling mechanisms for backpackers. It would be relatively light in your pack and can get a location noticed if you got lost. I'll have to dig through this site for simple designs that are easy to keep up in the air.

[TremendousJudge]

Sounds useful but in limited situations -- open fields (so no forests) and windy but not too windy

[silentguy]

Helium balloon would be a better option. Release it with other end tied to your backpack.