Some of it depends on what your child already plays with.

I actually avoided balls because my kids are insane with them. We would have been personas non gratus's by the end of any flight if I had allowed them on board.

Finger puppets are a good idea. Books with flaps that opened were a favorite with mine. Get the chunky kind. Actually, any book with moving parts was a hit. They could move the parts over and over and it makes no noise and is easy to pack.

Mine loved stackable toys, things that fit into one another.

We did well with just a bunch of plastic things. A few cars and plastic dinasaurs. Pin wheels, pipe cleaners, stickers, one parent said a roll of tape was very entertaining!

I found that successful squishy ball we used to have;
http://www.onestepahead.com/catalog/...tegoryId=85231

One Step Ahead is a good source for toys.

I personally think he's too young for any sort of videos. Those have to be watched either without sound or with the headphones.

I will mention the child-safety issue. I have to say that on the plane, if a parent is with him the whole time, evaluate the toy yourself. That "under 3" category really limits the selection. For example, a rubber ducky is usually not recommended for under 3's. I would give mine rubber toys, under supervision of course (I think it's because a baby could drink the water from them because some rubber things without holes were okay for that age). Same with anything magnetic or if it's a choking hazard.

Warning; some toys seem quiet but when you squeeze or shake them, less the case!