Plans for a new terminal at Orlando International Airport are moving quicker than expected.

Wednesday afternoon the Greater Orlando Aviation Authority approved a new plan that could have a new south terminal partially open by 2019.

They say it is needed sooner than planned to keep up with growing number of passengers.

"We are going to grow and we need to be prepared to deal with that demand," said GOAA Chairman Frank Kruppenbacher.

Ahead of Wednesday's vote, economist Dr. Sean Snaith from University of Central Florida laid out the future growth of OIA.

Right now the airport is close to breaking record numbers, serving around 36.4 million passengers a year. By 2020, Snaith estimates that number will grow to 45 million people.

Airport officials said they won't be able to keep up with that many passengers without the south terminal and they are already experiencing peak activities that go beyond the ultimate capacity.

The vote Wednesday means as soon as the airport hits 38.5 million passengers a year, construction will begin on the south terminal.

It will be built about a mile south of the north terminal and serve not only domestic passengers by also more foreign passengers. It's expected to bring cheaper and more direct international flights.

Airport officials said the need for more foreign flights is critical with more international passengers visiting Orlando than ever before.

Both Orlando Mayor Buddy Dyer and Orange County Mayor Teresa Jacobs sit on the board and agree starting construction sooner rather than later is for the better.

"I've seen other airports that have lagged in moving forward and we simply can't afford to do that," said Mayor Jacobs.

Not everyone is happy with the decision, specifically Southwest Airlines, the largest carrier at OIA.

Spokesman Pete Houghton gave this statement to News 13:

"With more than 8.6 million Customers flying to and from the Orlando International Airport each year on Southwest Airlines, we value the operation and the product we have in Orlando.  As the airport’s largest carrier, based on daily domestic departures, and with more than 100 daily nonstop flights, keeping costs low and providing a safe and reliable operation for our Customers is our number one priority.  With the Airport’s request to move up the design phase and to begin construction early, we remain concerned about total project costs which can drive up our operating costs, making it difficult to keep our fares low for our Customers."

The new south terminal is expected to cost about $1.8 billion.