Imaginetics Magnetic Playboards ($5-8)
Magnetic play sets, like the Imaginetics one pictured here, can pass the time onboard a long flight. Kids can make up stories about the characters, move them from scene to scene and even play games with the magnets.
The playboards come in a variety of themes - from Sesame Street and My Little Pony to Bob the Builder and fire houses. They also come in two sizes, so you can choose the perfect one for your carry-on bag.