After the BGA published a multi-part investigation into O’Hare International Airport in July, nearly two dozen readers sent us questions and comments about the airport and our story. Below, reporter Alejandra Cancino answers a few lingering questions submitted by readers.

How did you decide to focus on O’Hare over other city projects?

Because it’s the most complained about of all the major infrastructure projects in Chicago. Last year, Mayor Rahm Emanuel unveiled an $8.5 billion construction project to expand O’Hare. That project, named O’Hare 21, comes as the city continues work on a previous expansion plan that is six years behind schedule and billions over budget. That made us wonder, what were the promises made during previous expansions and what was delivered? We found a history of corruption, broken promises and costly disappointments at O’Hare.

Who pays for construction and modernization projects at O’Hare?

Taxpayers do, because the taxpayers own the airport and all the money generated there belongs to them. More granularly, however, airport users pay through fees and taxes levied there. Last year, the city collected $1.3 billion in O’Hare revenue. The money is collected in a special city fund used to pay for the airport’s day-to-day operations, maintenance and construction. That revenue comes from a range of sources, including landing fees paid by airlines and fees, or taxes, tacked on to airplane tickets and parking fees. The city also collects revenue from advertisement, sales of merchandise and from restaurants that operate at O’Hare. To pay for expansions, the city issues bonds, a form of debt issued by the city and paid back via revenue collected from O’Hare. As of December 31, the city’s bond debt was $18 billion.

What’s the deal with projects already underway at O’Hare? Is there a way to ensure they’re completed on time and on-budget?

Ask Mayor Lori Lightfoot, who took office in May on a promise to eradicate influence peddling from City Hall, and who inherits two ongoing multi-billion dollar overhauls there. We have been trying to ask her for months, even before she took office. Her administration has ignored multiple requests to speak with the BGA about its investigation. It’s unclear what, if anything, she would do to ensure history doesn’t repeat itself at O’Hare.

History has a penchant for repeating itself at the airport. As part of O’Hare 21, the city plans to raze Terminal 2 and build there a $2.2 billion Global Terminal. It will mark the city’s fourth attempt at building a terminal to house international travelers. The current international terminal, Terminal 5, will get 10 new gates, expanded security lanes and new baggage handling systems. It will mostly house domestic travelers, though some international travelers will continue to use Terminal 5. The city began Terminal 5’s renovations in March. They are expected to cost $1.2 billion.