If you're looking for manga similar to Kuusou no Sora Tobu Kikai-tachi, you might like these titles.
Komasuke is a young boy being raised by a thief in the 19th century who stole him from his rightful parents, and he’s trying his best to reform the woman who is raising him. But he is also the son of a time traveler from the 22nd Century, who has left for him a legacy until they can be reunited.
Takeru is a Japanese boy and swordsman who has traveled to China with hopes of making it all the way to Rome in order to meet a famed Roman swordsman. He begins his journey on the famed Silk Road, which by coincidence the Roman is also traveling – from the other direction.