Translation:It is a long flight between Europe and America.
We don't use "the" in front of names (proper nouns) unless that is part of the name. It's usually because the country or area has a plural name that it gets "the":
- The United States of America
- The Netherlands
- The Balkans
"The Americas" is the continents of both North and South America, and there aren't any other Americas which is why we use the definite article here.