Yes, both domestically and internationally, had no probs travelling with lights in carryon, on person, or in check in.
Nothing big or fancy. Recent trip, I had a RiverRock 2AA, and a coupla Dorcy 1AA modded with a 1/2 Watt 8mm LED and coupla Dorcy 1AAA modded similarly.
Once, they did ask me to...