As for the plane, my boys both have I devices and we also have Kindles, our flight is only 2 hours and the only one I'm worried about is my 5 y.o. but I think his Ipod touch will hopefully do the trick.
As for lines, this is going to sound totally off the wall, but I wait in a lot of lines that aren't theme parks, banks, restaurants, etc....and my 5 year old is getting more mature now and gets embarrassed, but this is what worked when he was 4 and younger: I would ask him if he could hop on one foot, then I would do it too, we would see who could hop the longest, then we jumped rope in place and tried to outdo each other, then we played 'copycat' where I would do something like a jumping jack and he had to copy me, then I might football feet in place while blinking my eyes really fast, crazy things like that. He loved it and I'm sure it was entertaining for those around us, lol. One time at a fast food place, other kids joined in. Good to get the energy out and distracting from long waits too.
Blessings, Michelle