What was your experience in flying with a child on your lap?
Statistically, lap children on airplanes are safer than many other situations we allow our children to be in on a regular basis. My DD flew as a lap child several times. Once DH came long, and the rest of the time it was just she and I.
I never flew with markers/crayons until DD was at least 3. The most popular items were..
An empty drink cup and some paper game pieces (put them in the cup, take them out of the cup, hand them to mom, take them from mom, shake the cup.. there was no end)
Temporary tattoos
reciting favorite books/never ending stories
Looking out the window, or looking at the route maps in the airline magazines and seeing where we were/where we were going
stickers (to be applied to self/clothing/mom)
Even on the last trip - coloring didn't last long, we did lots and lots of spelling, talking, singing, storytelling, poker, etc. Your child is a little young for poker, but not that card games that require a table (hold-em) really doesn't work well on an airplane. During ascent/descent the cards go everywhere.
We brought lots of snacks, the favorite blanket, one stuffed animal, etc.