Complex sentence: The main passenger airport serving the metropolis and the state is Melbourne Airport (also called Tullamarine Airport), which is the second busiest in Australia, and the Port of Melbourne is Australia's busiest seaport for containerised and general cargo.
Split into simpler sentences: The main passenger airport serving the metropolis and the state is Melbourne Airport (also called Tullamarine Airport), the second busiest in Australia. The Port of Melbourne is Australia's busiest seaport for containerised and general cargo.