Tip: Stick to canned versions packed in check-in bags.
Dried sausages confound X-ray machines–their density is simply too similar to Semtex, a plastic explosive.
Tip: Declare your precious Italian charcuterie as you would a treasured laptop.
Boomerangs are licensed to fly on flights within Australia, but not to the U.S., where they're on par with nunchucks and other gear the Teenage Mutant Ninja Turtles would have hand on.
Tip: Wrap tightly, pack, and check them if you're fond of Down Under toys.
Any booze over 140 proof (70%+ alcohol) is strictly prohibited at high altitude.
Tip: Leave that bottle of Bacardi 151 where it belongs, back on the beach and only in your (somewhat hazy) memory.
Tip: Declare formulas, breast milk, and juices for little ones at the outset. It should, soon, be acceptable (look to Europe for new laws regarding this and removal of shoes).
Knitting Needles: metal needles run a high risk of getting confiscated.
Tip: Pack the bamboo version (made in Japan) or learn how to use circular ones–they're both far less conspicuous and potentially threatening.
Gel soles: Remember, those 3.4 ounce rules apply to liquids and gels. Gel insoles, gel masks, and gel-type candles are all on the "nope" list.
Cellos or large musical instruments? Many musical travelers book extra seats for their instruments.
Tip: Give your fiddle a name–Joe Stradivarius, for example–and it'll be less likely to be off-loaded and banished to cargo.
Powerboards (aka "balance gliders" or "hoverboards") are seemingly everywhere this season, despite being banned on public streets in the U.S., U.K., and Australia. Updated 12/11/15. Airlines like JetBlue prohibit the toys as either carry-on or checked luggage, noting that they qualify as neither a medical assistance device or a personal electronic device (such as an iPad or laptop). Delta, United, and American Airlines are the latest airlines to ban hoverboards, joining British Airways, Virgin America, Alaska Airlines...the list goes on.
The greatest concern? A hoverboard's lithium ion batteries, which are considered Dangerous Goods and can—and have—caused fires on airplanes.