Patapata Hikousen no Bouken

The protagonists of both stories are cheerful and curious kid characters, who like to explore the world and expand their knowledge. Both are on a journey full of adventures, during which they get in a city with similar layout and social structure, but due to different reasons. The protagonist's are both held in high esteem by the city's leaders, who have questionable morals. Because of that, their relations to the protagonists do not quite proceed in the most amicable way... In both titles, situations and characters share some similarities. However, the reasons that led the characters to be what they are and the situations to occur are different. Also the reactions and developments of the characters may differ. Watching both shows may be interesting, if you want to see adventure stories in which similar characters respond differently to similar situations. read more 

The series are sharing a warmhearted and touching story. Each with a kind girl (as main character) who learns about the world. A saying that applies to both series: "The tool/animal is not evil itself, but in the wrong hands, it can be used for evil." They are going for their journey, will you accompany them as they grow?  

Both titles feature a child protagonist going on an adventureous journey filled with action and mystery. The backgrounds are heavily influenced by older Science Fiction titles. These series somehow felt like Jules Verne's works somehow. If you like an action adventure in a retro futuristc setting, these titles may be for you. 

Despite the plot being quite different, the Secret of Cerulean Sand definitely has the same feel as Laputa: Castle in the Sky. Jane's adventure reminded me of Pazu's and Sheeta's in a lot of ways: in search for the truth, making new acquaintances and friends, using their skills in regards to flying machines, facing the harsh realities of life and discovering oneself in this life changing epic journey. The theme of new technology and its uses was also a link: the tool is not evil but the people that use them with bad intentions are. Of course being a series, The Secret of Cerulean Sand has fleshed out characters but Laputa can still hold its own as a masterpiece of cinema. If you like this series, I recommend you watch Laputa and visa versa. read more 

Similar feel to Future Boy Conan. Both are great adventure stories. 

Both are heavily inspired from Jules Verne's stories, "20,000 Leagues Under the Sea" for Nadia and "Facing the flag" + "The Barsac Mission" for Patapata Hikousen no Bouken. They both capture a grand sense of adventure in foreign countries with a charming old style of storytelling and steampunk elements mixed into it. 

the art style and feel are the same, if you like one you will like the other