Complex sentence: The Avia 156 was a 1930s Czechoslovakian 6-passenger commercial transport for both mail and passengers designed by Robert Nebesář and built by Avia, the type performed well but only one was built.
Split into simpler sentences: The Avia 156 was a 1930s Czechoslovakian six-passenger commercial transport for both mail and passengers, designed by Robert Nebesář and built by Avia. The type performed well but only one was built.