Wandering Island, Vol. 1 (Wandering Island, #1)

From Book 1: First new work by Kenji Tsuruta (Spirit of Wonder) in 20 years!
Mikura Amelia is a free-spirited young woman who lives alone with her cat and operates an air delivery service, flying her vintage seaplane to Japan’s small island communities located hundreds of miles out in the Pacific. When her beloved grandfather passes away, she discovers he left her an undelivered parcel, addressed to an island that doesn’t exist . . . or does it? To answer the question, Mikura flies off in search of the truth behind the Wandering Island!
* Retro flying adventure in the spirit of Hayao Miyazaki.