This parcel post stamp shows an airplane (or aeroplane) carrying mail – possibly parcels, if they don’t weigh to much.
This 39c airmail stamp honors Lawrence Sperry and his father Elmer Sperry who were both aircraft designers.
This 40c airmail stamp honors Philip Mazzei.
This 31c airmail stamp honors the Wright brothers.
This 31c airmail stamp shows two globes as part of a stylized plane and flag.