Complex sentence: Modlin Mazovia Airport is an international airport, formerly a disused military airfield, which opened in July 2012, intended for low-cost carriers serving Warsaw, the capital of Poland.
Split into simpler sentences: Modlin Mazovia Airport is an international airport, formerly a disused military airfield, which opened in July 2012. The airport is intended to be used by low-cost carriers serving Warsaw, the capital of Poland.