Windows are rattling all over Chicago this afternoon, with the woosh of fighter planes heard in offices, shops and homes. That can mean only one thing: it’s time for the Chicago Air and Water Show, the biggest tourism event of the summer.

About 2 million spectators are expected to watch the show on Saturday and Sunday, but residents got a preview during rehearsals today that could be heard inside the Navy Pier studios of our partner WBEZ.

The show, which costs about $600,000 to put on, is paid for by corporate sponsors, according to Cindy Gatziolis, a city spokeswoman.

“We’ve certainly seen the effect of the economy, but we’re starting to see the return of folks spending their marketing dollars,” Gatziolis told the Chicago Tribune. “The Air and Water Show is such a strongly supported event, it seems to be one that’s a little bit immune from the economy.”

The show is in its 53rd year, and has grown from water skiers and divers to a full-fledged display of military might, with the B-1 Lancer expected to make an appearance along with the U.S. Air Force Thunderbirds. There also will be rescue helicopters, aerialists and planes flying in formation.

A chopper lifts off/Micki Maynard

The prime viewing area, stretching from Oak Street Beach up to Lincoln Park, also is lined with recruitment booths and marketing displays.

The festivities will be underway each day from 10 a.m. to 3 p.m. (ending a year earlier than in the past).