Two chairs stood empty, draped in white, as the 15 remaining graduates of Bishop Donahue High School (search) struggled to find joy in what should have been the biggest day of their lives.

Missing from the ceremony Tuesday were JoBeth Gross (search) and Danielle Block (search), athletes and honor roll students who died when their plane crashed on New York's Coney Island (search) during a weekend trip celebrating the end of final exams.

Salutatorian Caroline Horacek crumbled as she tried to quote Dr. Seuss, getting as far as "Congratulations, today is your day ..." before the tears began to flow.

"JoBeth and Danielle had extraordinary lives," she said. "They helped more people in 18 years than most of us ever will."

Brother Rene Roy, the school's principal, urged students to keep their faith in God and know that they have not been abandoned.

"Your class motto itself — every ending is a new beginning — is a note of confidence in the future, for beginnings always seem to connote new life," Roy said.

Across the gymnasium, tears fell with abandon as the victims' families took the stage to accept their diplomas. The graduates, wearing green and gold caps and gowns, posed for photos with each other and tried to ignore reporters and photographers standing nearby.

Gross' grandfather held his head in his hands, weeping into a blue bandanna.

McMechen, about 60 miles southwest of Pittsburgh, is more of a neighborhood than a town, with just 1,800 residents. Many students in the steel-town suburb say the small-town feel of their school has helped them cope.

"That family aspect has helped me through this," junior Philip Erickson said. "I don't think I could have gotten through this without it."

The Cessna 172S (search) plummeted to the ground Saturday after its engine apparently stalled while circling above the beach, witnesses said. Block's father, William Courtney Block, and pilot Endrew Allen also died in the crash, which remains under investigation.

No one on the ground was injured.

Danielle and JoBeth were part of a group of friends dubbed "the four musketeers." Another "musketeer" initially had been on the plane with her two friends, but got sick and asked the pilot to take her back to the airport, Roy said. After the pilot returned, Courtney Block got on the plane in her place.

For the Gross family, the plane crash is the latest in a string of heartbreaks: Gross' mother died of cancer nearly seven years ago, her grandfather is dying of cancer now, and her father is permanently disabled from a work-related accident. Two years ago, Gross' aunt was shot to death, and a year before that, a flood destroyed the Gross family home.

Bob Gross planned to borrow money to pay for his daughter's funeral, but the financially struggling school stepped in to raise money.

"My daughter's last four years at Bishop Donahue were the best four years of her life," Bob Gross said in a prepared statement. "She had unconditional love for her school and classmates."

Jay Park, a junior transfer student from South Korea, said Block and Gross were first to befriend him.

"Pretty much every positive adjective you can use in English applies to them," he said.

Freshman Ed Berardi agreed: "They were some of the best people you could meet."