Simplify the following text for a Grade 13 native English-speaking person.
Original: The plan shows a phased expansion of the airport to a maximum capacity of 8 million passengers per annum , without the addition of a second runway , or significant expansion of the current airport boundaries .
Simplified: The plan shows an expansion of the airport to a maximum capacity of 8 million passengers per annum , without the addition of a second runway , or significant expansion of the airport boundaries .