Favorite chewing gum to help with the pressure in your ears

Dramamine, or one of those motion sickness bracelets you find at the pharmacy.

Silicone earplugs, or noise cancelling headset to drown out cabin noise

Eye mask to help you sleep

Avoid any stimulants before boarding

Device with favorite movies or music

And know that statistically, you are 100x safer in an aircraft, than in a passenger vehicle.