EL CAJON, California (AP) -- An elderly man recently diagnosed with a brain tumor leaped to his death from a vintage airplane he rented to celebrate his 88th birthday, officials said Tuesday.

Joseph Harold Frost took off his safety belt at 300 to 400 feet, stood up in the open cockpit of the two-seat biplane and went over the side Monday.

The pilot tried but failed to wrestle him back into the plane and nose the aircraft upward to force Frost back into his seat.

"I think that was Dad's idea, to go out in a flash of glory," said Robert Frost, who had helped his father arrange the chartered flight on a biplane similar to the ones the elder Frost flew in World War II.

The man landed on an apartment patio, horrifying those who witnessed it.

"I saw him hit the power lines, heard trees breaking. I really thought it wasn't real," Cynthia Lankford said.