Updated

Since the start of 2014, more than 1,600 people have died in commercial aviation disasters. That rate is up from the preceding three years and results in part from some shocking incidents, including a pilot suicide and the downing of a passenger jet over Ukraine by an anti-aircraft missile.

Yet a strong case can be made that airline safety — at least in terms of mechanical failures and human error — is better than ever, even as investigators try to learn why an EgyptAir jetliner crashed into the Mediterranean Sea on Thursday with 66 people aboard.

Assuming all 66 are dead, the toll from four commercial airline crashes this year is 163. By contrast, more than 1,000 people a year died in plane crashes between 1991 and 1998.

In regard to disasters, 2014 and 2015 were among the most dramatic in recent aviation history.

In March 2015, 150 people aboard Germanwings Flight 9525 were killed when one of the pilots deliberately flew the plane into a mountainside. In October, a Metrojet airline exploded over the Sinai Peninsula, killing all 224 people on board, in what was determined to be a terrorist bombing.

The International Air Transport Association tallied only four other commercial airline disasters in 2015 — all crashes involving turboprops rather than jetliners. The death toll from those four crashes was 136; including the Germanwings and Metrojet incidents, the toll for the year was 510.

In 2014, according to IATA, there were 12 fatal airline accidents, with 641 fatalities, including the still-unsolved case of Malaysia Airlines Flight 370, which disappeared from radar over the Gulf of Thailand with 239 people on board.

An additional 298 people were killed when Malaysia Airlines Flight 17, en route from Amsterdam to Kuala Lumpur, was shot down over eastern Ukraine in July 2014. Including that incident, which IATA does not classify as an accident, the overall air disaster death toll for 2014 was 939.

"To the flying public, an air disaster is an air disaster," said Perry Flint, an IATA spokesman. "But the industry needs to make a distinction between something that was unintended, and something that was done deliberately, in order to be able to take appropriate action to reduce the likelihood of something similar occurring in the future."

IATA, which represents about 260 airlines accounting for 83 percent of air traffic, says there was only one serious jet accident per every 3.1 million flights in 2015.

"Aviation is the safest form of long distance transportation ever invented. And it is getting safer," Flint said. "All the data point in that direction."

The flying public appears to accept those assurances, as air traffic records are being broken in virtually every region of the world.

Airlines for America, the lobbying group for most U.S. carriers, predicts that 231.1 million passengers will fly in June, July and August — a 3.8-percent increase over last summer's record numbers.

Indeed, the high demand for flying has contributed to long lines at many security checkpoints. Airlines are urging fliers to get to the airport earlier than usual.

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AP Business Writer Scott Mayerowitz contributed to this report.