As far as flight-safe grinders, I've seen this topic come up before on forums and mailing lists and always heard good reports regarding carrying on a hand grinder, but it always helps to have some coffee with it so you can explain what it's for.
I bought the Kyocera CM-45 CF as my first espresso grinder, which I eventually replaced with a Vario. I've also used it camping and traveling and it now is part of a
MyPressi Twist espresso case where it continues to serve.
You may want to read my review of my experiences with the Kyocera CM-45 CF
here. Overall, I'm satisfied with the grind quality, but there's durability concerns with this and other small grinders you should be aware of.
I recently scored a Hario Slim grinder new-in-box at a thrift store for $5. I took it to work and set it for pour-over grind (Aeropress with Disk or Clever Coffee Dripper) and keep the Kyocera dialed in for espresso. For the difference in price (new), you may want to consider one of the Hario's over the Kyocera CM-45 CF, or if you really want to go small, I've heard that the Porlex which shares the burr set of the Kyocera CM-45 CF can fit inside the small plunger of the Aeropress.