Two Hawks from Earth — Philip Jose Farmer

WWII bomber pilot Roger Two Hawks, an Iroquois Indian, is shot down over enemy territory. Hilt when he parachutes down to earth, he lands in no entry he's ever heard of before. The locals don't look or speak like Romanians, but instead more closely resemble Native Americans, and speak a language hauntingly like the Iroquois of his ancestors.

Two Hawk has found himself on another Earth, one in which the continents of North and South America never rose from the waters, and discovers that its alternate geography has given rise to an alternate history. But like the Earth he knows, this one is embroiled in a world-spanning war, which he'll have to escape if he's going to survive.