Just how well did last summer's inaugural Firefly Music Festival succeed in making a name for itself?

So well that this year, twice as many people showed up. Starting Friday, when the Red Hot Chili Peppers headlined, the three-day, 77-band gathering at the Woodlands of Dover International Speedway drew 60,000 people a day to the expanded 87-acre site hard by Route 1, 1 1/2 hours' drive from Philadelphia.

Numbers-wise, that puts Firefly in the big leagues, getting in the neighborhood of long-standing mega-fests like Bonnaroo and Coachella, which pull in upwards of 90,000 a day. And talent-wise, Firefly is impressively competitive, as well.

On Saturday night, old, reliable, classic rock hitmakers Tom Petty & the Heartbreakers topped a bill that included rappers Azealia Banks and Kendrick Lamar, My Morning Jacket main man Jim James, psychedelic duo MGMT, soul-rock outfit Alabama Shakes, Scottish electro-pop band Chvrches, and art-punk trio Yeah Yeah Yeahs.

"This is great for us," said a bearded Petty, playing his first-ever show in Delaware. The day's strongest smell of weed smoke wafted through the crowd after "Mary Jane's Last Dance." Petty gestured toward the cloudless sky where a bright orb shone above, providing the picture-postcard moment that the sagging Firefly hot-air balloon near the stage couldn't seem to achieve. "You know we've got this crazy moon up there. That's got to be good for music."

It seemed that it was. Firefly, presented by Red Frog Events, a Chicago company that otherwise specializes in putting on "Warrior Dash" mud-run obstacle course races, drew a crowd of mostly 18- to 35-year-olds doing the things people at weekend-long music festivals do.

Such as carrying around inflatable killer whales. Or holding up sticks on which a picture of Kevin Bacon's head is attached to a body made of . . . bacon. Or wearing American Indian headdresses. Or the most popular option: Lying on their backs in a field, staring up through sunglasses, and singing along to songs like Lamar's "B-, Don't Kill My Vibe."

Petty's set, which kicked off with a cover of the Byrds' "So You Wanna Be a Rock and Roll Star?," sounded sharp, but was marred by overcrowding. At that point - 10 p.m. to midnight - the headliners were the only act performing, and with the entire crowd focused on the main stage, there was too much talking, jostling, and drunken stumbling to enjoy the show.

With hi-def video and superb sound (and no sonic bleeding among the four far-flung stages) every other set I saw was more than pleasant, however. Toward the top of them was Banks, the motormouthed and often profane Harlem rapper. One of these days maybe, her oft-delayed debut, Broke With Expensive Tastes, will actually be released.

Contact Dan DeLuca at 215-854-5628, ddeluca@phillynews.com, or follow on Twitter @delucadan. Read his blog, "In the Mix," at inquirer.com/inthemix.