The big airport is getting a big facelift. Terminal B at George Bush Intercontinental Airport is now under construction.

The groundbreaking for a $1 billion renovation project started Monday morning.

The joint venture between United Airlines and the Houston Airport System will replace the existing flight stations on the terminal's south side.

The 225,000-square-foot facility is almost four times the size of the existing space, which was built in 1969.

"It's ready for an upgrade and ready to move into this century," Houston Mayor Annise Parker said.

Bush Airport serves more than 40 million passengers each year and airport leaders said the renovation is needed.

"Houston is our largest hub and a vital international gateway in United's network," said Pete McDonald, United Airlines' executive vice president and chief operations officer. "The investment in the Houston hub will allow us to accommodate more customers and more aircraft types, provide new amenities for travelers and improve efficiencies for the new United."

There will be larger boarding areas and a better gate layout.

Restrooms and restaurants in the terminal are also getting a massive makeover. The lobby and baggage claim areas will be redeveloped.

In addition, over the next seven to 10 years, more than 600 jobs will be created because of the project.

"The jobs opportunity is great," McDonald said. "This is a great day for Houston and United."

"As I noted in my inaugural address, creating jobs for Houstonians is my No. 1 job for the next two years," Parker said. "Phase one of this billion-dollar investment with United is the first delivery on that promise."

The first phase of the project is expected to be finished in late 2013.

Officials said travelers should not be delayed because of the construction project.

• Houston Airport System: Bush Intercontinental and Hobby Airports

• Aeromexico

• Air France

• AirTran Airways

• American Airlines

• British Airways

• Continental Airlines

• Delta Airlines

• Frontier Airlines

• JetBlue

• KLM

• Lufthansa

• Northwest Airlines

• Qatar Airways

• Saudi Arabian Airways

• Singapore Airlines

• Southwest Airlines

• TACA Airlines

• United Airlines

• U.S. Airways