A number of similarities exist. Fam hunts Skyfish, and Sam hunts sand whales, both of which use the term "kujira" for "whale" in the original Japanese. Both characters are somewhat carefree and rescue a princess, drawing them into a greater conflict. In both worlds, ships use the skies and the ground as their "ocean".
Similar series, featuring airships and pirates, however Ozuma takes place in a desert environment. Last Exile: Fam the Silver Wing is probably the superior, but both are Science Fiction future earths with steampunk-ish technology.
Same creator, and someone with knowledge of one will recognize the art style of the other. Ozuma really feels like Captain Harlock but in a desert, instead of space and with a female commander. However, they aren't reiterations of each other, despite the incredible similarities and both are unique. Ozuma is also a bit more light-hearted and has more animated/emotional characters, whereas the characters in Harlock can sometimes feel static and lacking in personality, development or motive.
Similar series, featuring airships and pirates, however Ozuma takes place in a desert environment. Last Exile is probably the superior, but both are Science Fiction futures with mysterious girls and a Harlock-esque pirate-like captain and spunky young male lead.
Space pirates and sci-fi action are themes both present in these two anime(s). Additionally, there is comedy, action, great soundtrack, and inklings of romance in Ozuma. (more so in Elemental Gelade). The mystery involved in both of these series are also present as revelations are made and plot holes are formed.
The resemblance is given in the rescued girls, because in both animes are a girl who must save or cure but then realize that it's more than that. In Ozuma because Maya is important for being an 'original' able to call to Ozma, while Odin is Queen Sara is searching the Odin planet.
Upon meeting these girls the story of his rescuers change and undertake new goals.
Similar desert climate with futuristic technology. Both involve a boy unexpectedly encountering a girl with ice blue hair and eyes and trying to save her from being captured. If you thought Ozma was at least decent then definitely try out Now and Then, Here and There!
Young, streetwise guys who know what they're doing are looking after an innocent, mystery, blue haired girl who was on her own within a conflict environment.
Neither of these anime's are set in our time period.
Like Ozuma, this anime is set in the not so distant future where the vegetation on earth has completely disappeared, leaving a sand-filled landscape. The main character, Hitomi, is also a lone traveler who is not necessarily engaged in trade but offers her services up as a mercenary.