I think all the airlines still serve beverages (sodas, tea, juice, coffee, water, etc.) at no charge. Alcoholic beverages are usually served, too, but you must buy your own, unless of course, you are flying first class! Many still give out pretzels or cookies as a small snack in lieu of a meal. You can check it out on your airline's website.
You can bring anything you want to eat on the plane. I have seen many people with pizza, burgers, etc., purchased in the airport. Last flight I was on, a couple had bbq rib dinners. They really seemed to enjoy it, however, I have to say that the smell disgusted me. Not that I don't love bbq myself, it was just that the smell lingered for the majority of the flight.
I would suggest you take whatever you enjoy, but be considerate of others and take things that don't have an overpowering odor. We always take snack type foods or if it's early, donuts or cinnamon rolls for the kids.
Have a great trip!
dizneyfan