5 hour flight with 3 month old - Tips needed!

Hi all, taking our first flight with our 3 month old from NJ to AZ in a month to visit my parents. Any advice on breastfeeding on a flight, what I should take on the flight for her or how to keep her calm? Basically any and all advice is much appreciated! I am nervous. My husband flies back to NJ a day earlier than me and baby girl and I are doing the return flight alone. 😯😲 nervous is an understatement!