PITTSBURGH, Pennsylvania (CNN)  -- For Pittsburgh International Airport, the Group of 20 summit is like the Sunday after Thanksgiving: the busiest flying day of the year, with world leaders instead of holiday travelers.



Officials greet Saudi Foreign Minister Saud al-Faisal, left, on Wednesday at Pittsburgh International Airport.



After weeks of logistics and planning, the airport and the adjacent Air Force Reserve Base will see 23 heads of state arrive in the space of a few hours.



President Obama is hosting the G-20 summit -- a two-day meeting of representatives of the world's largest economies -- Thursday and Friday in Pittsburgh.



"This is unprecedented," Allegheny County Chief Executive Dan Onorato said. "We've never seen anything like it."



The county runs the airport and coordinated the arrivals along with the White House, U.S. State Department and law enforcement officials.



The arrivals will take place away from the commercial passenger terminals on the huge airport property. With different areas being used, some of the presidents and prime ministers will show up at the same time.  Watch Pittsburgh's security preparations for protesters »



"It is all scheduled. No one will be sitting out" on the tarmac waiting, Onorato said.



There are no welcoming ceremonies planned at the airport. The leaders quickly will get into separate motorcades and be whisked to downtown Pittsburgh.



A formal greeting will take place Thursday evening at a conservatory in Pittsburgh's Oakland neighborhood.



The heads of state invited to Pittsburgh include the leader of the European Union and the prime ministers of the Netherlands, Spain and Sweden.



Many leaders are bringing hundreds of delegates and support staff with them as well. At least two countries are bringing jumbo jets into the airport. Members of Saudi Arabia's delegation landed Wednesday evening.



The leaders are arriving from New York, where they attended the U.N. General Assembly.



Airport officials say the VIP landings will not mean delays for passengers, though they warn trips to and from the airport could take extra time because of road closings for motorcades.



It's Obama's second trip to Pittsburgh in nine days. He addressed the AFL-CIO Convention on September 15 at the David L. Lawrence Convention Center, where the G-20 summit also is being held.



This time, Air Force One will have plenty of company.
Who meets for two days in Pittsburgh? Who is meeting in Pittsburgh? How long are they meeting for? What number of heads of state are arriving? Who is also on hand? How many heads of state are going?
representatives of the world's largest economies Group of 20 two-day 23 hundreds of delegates and support staff 23
question: Who meets for two days in Pittsburgh?, answer: representatives of the world's largest economies | question: Who is meeting in Pittsburgh?, answer: Group of 20 | question: How long are they meeting for?, answer: two-day | question: What number of heads of state are arriving?, answer: 23 | question: Who is also on hand?, answer: hundreds of delegates and support staff | question: How many heads of state are going?, answer: 23