I brought lipo both ways in many (international) airlines and usually it's not a problem.
If you keep it with you you need them protected and unplugged. They might bother you, so be early.. it can take an hour sometimes. (that include stuff like special scan, having them keep your batteries til landing etc etc)
If you don't keep it with you (my favorite solution now because waiting 1H sucks), put them protected in a lipo bag (and protect the lipo contacts).
Likewise for the radio and video equipment. They're annoying during the security scan more often than not.
I take the plane with me every time. Mine is small enough to fit the requirement (split Zephyr), strong enough to survive possible chocks etc (again, Zephyr - it did fall a couple of times while traveling ;p) and usually the pilot asks whats that big bag (the customs and security guards don't care they just scan it through a special scanner to make sure it doesn't emit any radio wave). And when you show them a plane, I have yet to meet a pilot that wouldn't be excited about it (especially when you show the on-board camera
I was using a plane in a foam box previously and it's a lot less convenient
ps: it always depends on the country, airport, period/time and person in charge, so when one thing works one time don't expect it to work again reliably