Yep, took my L0D to Miami and Pensylvania (business trips), then I got a quark AA neutral, so I started taking that one with me.
I kept the L0d in my pocket, but I put my Quark AA in my carry-on. No problems ever so far and I was on the plane at least 6 times last year, 4 of those international flights. I'll most likely bring it on longer trips too.
I haven't had to change any batteries in it, since I haven't used it so far while on a trip (aside camping trips, obviously). I feed it NiMh and have at least one NiMh spare just in case, but it would most likely be used in my MP3 player. I've had the same setup for 3 day trips, 5 day trips and up to 12 days trips (International, since I'm from Canada).