Which flight?
Oranges appear whenever death is in the air: When the Godfather gets shot in the street, he's buying oranges, which scatter on the ground as he falls. When Vito dies at the very end, its while peeling an orange and putting the rind in his mouth to make funny faces at his grandson. Before the horse head shows up in Jack Woltz's bed, we see an orange at the table where he eats dinner with Tom Hagen. Oranges show up at the meeting with the five families, near the mob bosses who will later be whacked.
https://www.shmoop.com/the-godfather/oranges-symbol.html