It is not that there isn’t loads and loads of foods and drinks at airports but it is usually not vegan, on the contrary the foods there are often processed foods with loads of salt and sugar, very unhealthy to say it the least. Yes fruits might be sold there but that’s too little to eat. Just remember if you bring along fresh fruits yourself you must eat it before landing, you are not allowed to bring fresh fruit into a new country.
DivineBagsofCells recorded this video on a layover in Oahu Hawaii.
https://www.youtube.com/watch?v=8XAdTgT4w4o